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读取二进制文件中的结构，存储在指针数组中，对其进行排序并将其写入另一个文件

[英]reading structs in a binary file, storing in an array of pointers , sort it and write it out into another file

 原文  2022-08-31 15:27:02  5   1    arrays/ c/ fwrite/ fread/ qsort

问题描述

我的作业有点问题。 正如标题所说，我的任务是将二进制文件中的结构读入指针数组，使用 qsort 对其进行排序并将其写入新的二进制文件。 问题是我从代码中得到的 output 与预期的 output 不同。 在 UNIX 中使用 cmp 显示第 1 行中的第一个字节与预期不同。

这是排序顺序：

Sorting order (in order of precedence):
 
tin in ascending order. 
tray in descending order. 
flavor in ascending order. 
lumber in descending order. 
sheet in descending order. 
yarn in descending order. 
stream in ascending order. 
fog in ascending order. 
volcano in descending order. 
organization in descending order. 
territory in ascending order. 
tax in descending order. 
church in ascending order. 
chicken in ascending order. 
trucks in ascending order. 
crush in descending order.

这是我的结构：

typedef struct {    //struct creation
    long organization;
    char tray;
    char chicken;
    unsigned int stream;
    short int church;
    char tax;
    short int crush;
    unsigned short int lumber;
    double volcano;
    float tin;
    char sheet;
    short int trucks;
    char territory[8];
    float fog;
    char flavor;
    unsigned short int yarn;
} database;

这是我对 qsort 的比较 function：

int cmp(const void * p, const void * q){
    database *a = (database *)p;
    database *b = (database *)q;
    
    /* float tin ascending order */
    if(a->tin > b->tin) return 1;
    if(a->tin < b->tin) return -1;

    /*char tray descending order */
    if(a->tray > b->tray)   return -1;
    if(a->tray < b->tray)   return 1;

    /*char flavor in ascending order */
    if(a->flavor > b->flavor)   return 1;
    if(a->flavor < b->flavor)   return -1;

    /* unsigned short int lumber in descending order */
    if(a->lumber > b->lumber)   return -1;
    if(a->lumber < b->lumber)   return 1;

    /* char sheet in descending order */
    if(a->sheet > b->sheet)   return -1;
    if(a->sheet < b->sheet)   return 1;

    /* unsigned short int yarn in descending order */
    if(a->yarn > b->yarn)   return -1;
    if(a->yarn < b->yarn)   return 1;

    /* unsgined int stream in ascending order */
    if(a->stream > b->stream)   return 1;
    if(a->stream < b->stream)   return -1;

    /* float fog in ascending order */
    if(a->fog > b->fog)   return 1;
    if(a->fog < b->fog)   return -1;

    /* double volcano in descending order */
    if(a->volcano > b->volcano)   return -1;
    if(a->volcano < b->volcano)   return 1;

    /* long organization in descending order */
    if(a->organization > b->organization)   return -1;
    if(a->organization < b->organization)   return 1;

    /* string territory in ascending order*/
    if(strcmp(a->territory, b->territory) > 0)  return 1;
    if(strcmp(a->territory, b->territory) < 0)  return -1;

    /* char tax in descending order */
    if(a->tax > b->tax)   return -1;
    if(a->tax < b->tax)   return 1;

    /* short int church in ascending order */
    if(a->church > b->church)   return 1;
    if(a->church < b->church)   return -1;

    /* char chicken in ascending order */
    if(a->chicken > b->chicken)   return 1;
    if(a->chicken < b->chicken)   return -1;

    /* short int trucks in ascending order */
    if(a->trucks > b->trucks)   return 1;
    if(a->trucks < b->trucks)   return -1;

    /* short int crush in descending order */
    if(a->crush > b->crush)   return -1;
    if(a->crush < b->crush)   return 1;

    return 0;
}

这是我的主要 function：

int main(int argc, char *argv[]) {
    FILE * fptr = fopen(argv[1], "rb");
    size_t fileLength, records;
    fseek(fptr, 0, SEEK_END);
    fileLength = ftell(fptr);
    fseek(fptr, 0, SEEK_SET);
    records = fileLength/STRUCTSIZE;
    database * testDatabase = malloc(records * sizeof( * testDatabase));
    
    if(argc <= 1 || argc >= 4){  //check if there are parameters
        usage();
        return 0;
    }
    if(fptr == NULL){    //check if file exists or not
        fprintf(stderr, "No such file or directory %s\n", argv[1]);
        exit(1);
    }

    else{
        for(int i = 0; i < records; i++){
            
            fread(&testDatabase[i].tin, sizeof(testDatabase->tin), 1, fptr);

            fread(&testDatabase[i].tray, sizeof(testDatabase->tray), 1, fptr);

            fread(&testDatabase[i].flavor, sizeof(testDatabase->flavor), 1, fptr);

            fread(&testDatabase[i].lumber, sizeof(testDatabase->lumber), 1, fptr);

            fread(&testDatabase[i].sheet, sizeof(testDatabase->sheet), 1, fptr);

            fread(&testDatabase[i].yarn, sizeof(testDatabase->yarn), 1, fptr);

            fread(&testDatabase[i].stream, sizeof(testDatabase->stream), 1, fptr);

            fread(&testDatabase[i].fog, sizeof(testDatabase->fog), 1, fptr);

            fread(&testDatabase[i].volcano, sizeof(testDatabase->volcano), 1, fptr);

            fread(&testDatabase[i].organization, sizeof(testDatabase->organization), 1, fptr);

            fread(&testDatabase[i].territory, sizeof(testDatabase->territory), 1, fptr);

            fread(&testDatabase[i].tax, sizeof(testDatabase->tax), 1, fptr);

            fread(&testDatabase[i].church, sizeof(testDatabase->church), 1, fptr);

            fread(&testDatabase[i].chicken, sizeof(testDatabase->chicken), 1, fptr);

            fread(&testDatabase[i].trucks, sizeof(testDatabase->trucks), 1, fptr);

            fread(&testDatabase[i].crush, sizeof(testDatabase->crush), 1, fptr);
        }
    }
    fclose(fptr);
    /* sorting */
    qsort(testDatabase, records, sizeof(testDatabase), cmp);
    
    /* writing */
    FILE * output = fopen(argv[2], "wb");

    for(int j = 0; j < records; j++){
        fwrite(&testDatabase[j].tin, sizeof(testDatabase->tin), 1, output);

        fwrite(&testDatabase[j].tray, sizeof(testDatabase->tray), 1, output);

        fwrite(&testDatabase[j].flavor, sizeof(testDatabase->flavor), 1, output);

        fwrite(&testDatabase[j].lumber, sizeof(testDatabase->lumber), 1, output);

        fwrite(&testDatabase[j].sheet, sizeof(testDatabase->sheet), 1, output);

        fwrite(&testDatabase[j].yarn, sizeof(testDatabase->yarn), 1, output);

        fwrite(&testDatabase[j].stream, sizeof(testDatabase->stream), 1, output);

        fwrite(&testDatabase[j].fog, sizeof(testDatabase->fog), 1, output);

        fwrite(&testDatabase[j].volcano, sizeof(testDatabase->volcano), 1, output);

        fwrite(&testDatabase[j].organization, sizeof(testDatabase->organization), 1, output);

        fwrite(&testDatabase[j].territory, sizeof(testDatabase->territory), 1, output);

        fwrite(&testDatabase[j].tax, sizeof(testDatabase->tax), 1, output);

        fwrite(&testDatabase[j].church, sizeof(testDatabase->church), 1, output);

        fwrite(&testDatabase[j].chicken, sizeof(testDatabase->chicken), 1, output);

        fwrite(&testDatabase[j].trucks, sizeof(testDatabase->trucks), 1, output);

        fwrite(&testDatabase[j].crush, sizeof(testDatabase->crush), 1, output);

    }
    fclose(output);

    /* release memory */
    free(testDatabase);

    return 0;
}

输入：

00000000: 00000000 00000000 00000000 00000000 00000000 00000000  ......
00000006: 00000000 00000000 00000000 01101100 00100101 10111110  ...l%.
0000000c: 01001101 10111010 00000001 00000000 00000001 00000000  M.....
00000012: 00000000 00000001 00000000 00000000 00000000 00000000  ......
00000018: 00000000 00000000 00000000 11110000 00111111 01000000  ....?@
0000001e: 11111100 11001001 01001011 00000000 10011000 01000100  ..K..D
00000024: 01100110 01101001 01110011 01101000 00000000 00000000  fish..
0000002a: 00000000 00000000 00000000 00000000 00111101 10111110  ....=.
00000030: 01100011 00000001 00000000 10101011 01001000 00001001  c...H.
00000036: 11110110 10000010 11100001 11010000 10000001 00000001  ......
0000003c: 10001111 00000000 00000000 00000000 00000000 00000001  ......
00000042: 00000000 00000000 00000001 00000000 10001011 11110011  ......
00000048: 00000000 00000000 00000000 00000000 00000000 00000000  ......
0000004e: 00000000 00000000 11001110 10001000 10000110 11001011  ......
00000054: 00000000 00110101 01101011 01100011 01101111 01110010  .5kcor
0000005a: 01101011 00000000 00000000 00000000 00000000 00000000  k.....
00000060: 00000000 10000000 00111111 01001100 00000000 00000000  ..?L..
00000066: 01011001 11111000 11111111 11111111 11111111 11111111  Y.....
0000006c: 11111111 11111111 00000000 00000001 00000001 00000000  ......
00000072: 00000000 00000000 00000001 00000000 00000000 00000000  ......
00000078: 00000000 00000001 00000000 00000000 00000000 00000000  ......
0000007e: 00000000 00000000 00000000 11101000 10111110 00000000  ......
00000084: 00000000 10000000 00111111 00000001 10010001 10011010  ..?...
0000008a: 01110100 01101111 01110101 01100011 01101000 00000000  touch.
00000090: 00000000 00000000 10011111 10101011 00010100 01001001  .....I
00000096: 01111101 00000000 00000000 01100000 10000000 00110111  }..`.7
0000009c: 10001110 00110100 11000101 00100000 10111010 00000001  .4. ..
000000a2: 00000001 10000011 11000100 10110110 11101000 00000000  ......
000000a8: 00000000 00000000 00000000 00000000 01101011 10111011  ....k.
000000ae: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000000b4: 00000000 00000000 00000000 00000000 11011100 10111111  ......
000000ba: 00000001 00000001 00000000 01101001 01110011 01101100  ...isl
000000c0: 01100001 01101110 01100100 00000000 00000000 00000000  and...
000000c6: 00000000 00000000 00000000 01101010 00000001 00000000  ...j..
000000cc: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000000d2: 00000000 00000000 00000000 11011110 10100100 11101010  ......
000000d8: 01011010 00000000 00000000 00000000 00000000 00000001  Z.....
000000de: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000000e4: 00000000 00000000 00000000 00000000 00000000 11000000  ......
000000ea: 00000011 01111001 01001000 00000000 00000001 00000000  .yH...
000000f0: 01101101 01100001 01110000 00000000 00000000 00000000  map...
000000f6: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000000fc: 00111010 00001110 00000000 00000001 00000000 00000000  :.....
00000102: 00000000 00000000 00000000 00000000 00000000 00000001  ......
00000108: 01100111 00000000 00000000 00000000 00000000 00000000  g.....
0000010e: 00000000 00000001 00000001 00000000 00001010 11100111  ......
00000114: 00000000 00000000 00000000 00000000 00000000 00000000  ......
0000011a: 11110000 00111111 00000000 00000000 10000000 00111111  .?...?
00000120: 00000001 00000000 00000000 01100010 01100001 01110011  ...bas
00000126: 01101011 01100101 01110100 00000000 00000000 00000000  ket...
0000012c: 00000000 00000000 00000000 01001111 10101111 00000001  ...O..
00000132: 01111011 11001110 00000011 00101001 10000111 10110011  {..)..
00000138: 01101011 01110111 00000000 00000000 00000000 00000000  kw....
0000013e: 00000000 00000000 00000000 00000000 00000001 00000001  ......
00000144: 00000000 00000001 00000000 00000000 00000000 10000000  ......
0000014a: 01011101 10000110 11011011 10100101 11000000 00000000  ].....
00000150: 00000000 10000000 00111111 00000000 00000000 00000000  ..?...
00000156: 01110011 01101111 01100011 01101001 01100101 01110100  societ
0000015c: 01111001 00000000 10011001 11110000 01110000 11001001  y...p.
00000162: 01010111 11100011 11000001 00000001 00000000 00000000  W.....
00000168: 00000000 00000000 00000000 00000000 00000000 00000000  ......
0000016e: 00011000 11111110 00111000 00000000 00000000 00000001  ..8...
00000174: 00000000 00000000 00000001 00000000 00001010 00000000  ......
0000017a: 00000000 00000000 10000000 01110000 11011001 10111110  ...p..
00000180: 10100110 01000000 00000000 00000000 00000000 00000000  .@....
00000186: 00000001 00000001 00000000 01100101 01100111 01100111  ...egg
0000018c: 01101110 01101111 01100111 00000000 00000000 00110100  nog..4
00000192: 01110001 00100011 01001001 01010111 00011111 01001111  q#IW.O
00000198: 00000001 00000000 00000000 00000000 00000000 00000000  ......
0000019e: 00000000 00000000 00000000 10111111 00000001 00000000  ......
000001a4: 00000000 00000000 00000001 00000000 00000000 00000001  ......
000001aa: 00000000 10110001 00001110 00000000 00000000 00000000  ......
000001b0: 01001101 00110110 01110001 10101001 01000000 10101101  M6q.@.
000001b6: 11010110 11110111 11001011 00000001 11011010 01001010  .....J
000001bc: 01100110 01110010 01100001 01101101 01100101 00000000  frame.
000001c2: 00000000 00000000 01010000 10111011 10100001 01000100  ..P..D
000001c8: 01010100 11101010 01100001 10111011 10011110 00000011  T.a...
000001ce: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000001d4: 01111110 01111110 10011101 10111010 00001011 00000000  ~~....
000001da: 00000000 00000001 00000001 00000000 10110001 00001101  ......
000001e0: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000001e6: 00111000 00111111 11010110 11100110 11111000 11001011  8?....
000001ec: 00000001 00101110 10000110 01110100 01100101 01101110  ...ten
000001f2: 01110100 00000000 00000000 00000000 00000000 00000000  t.....
000001f8: 00000000 10000000 00111111 01000101 00001011 00000000  ..?E..
000001fe: 11010011 11110011 11101100 01010110 00000101 10011000  ...V..
00000204: 10010110 00000001 00000000 00000001 11000100 10000001  ......
0000020a: 00011110 00000000 00000000 00000000 00000000 00000001  ......
00000210: 00000000 11100101 00000000 00000000 00000000 00000000  ......
00000216: 00000000 00000000 00000000 11110000 00111111 00000000  ....?.
0000021c: 00000000 00000000 00000000 00000000 10001101 10111010  ......
00000222: 01110111 01101000 01100101 01100101 01101100 00000000  wheel.
00000228: 00000000 00000000 10110011 11100111 00010110 11001001  ......
0000022e: 01001001 00001000 00000000 10111110 11010110 10101111  I.....
00000234: 01011100 00001111 11110101 10111000 10010111 00000000  \.....
0000023a: 00000000 01100000 01011001 00010011 00001001 00000000  .`Y...
00000240: 00000000 00000000 00000000 00000000 00010110 00001011  ......
00000246: 00000000 00000000 10000000 01111101 11011000 10011001  ...}..
0000024c: 10100000 11000000 11001000 00110101 11000101 01001011  ...5.K
00000252: 00000001 00000000 00000000 01110110 01100101 01110011  ...ves
00000258: 01110100 00000000 00000000 00000000 00000000 11101111  t.....
0000025e: 00101011 00110111 11001001 01111110 01110010 10100001  +7.~r.
00000264: 10011111 00000011 01010000 11011111 01010110 11111010  ..P.V.
0000026a: 01011101 01110011 00000001 11010111 00001111 00111110  ]s...>
00000270: 00000000 00000000 00000000 00000000 00000001 00000001  ......
00000276: 00000000 00000000 00000000 00000000 00000000 00000000  ......
0000027c: 10000000 00111110 11000111 00100010 01000000 01111100  .>."@|
00000282: 00110100 10010000 01001011 00000000 00011000 11111110  4.K...
00000288: 01110011 01100011 01101000 01101111 01101111 01101100  school
0000028e: 00000000 00000000 00000000 00000000 10000000 00111111  .....?
00000294: 01001100 01000111 10111000 00000000 00000000 00000000  LG....
0000029a: 00000000 00000000 00000000 00000000 00000000 00000001  ......
000002a0: 10111001 10100100 00100100 00100001 11111101 00000001  ..$!..
000002a6: 00000000 00000001 00000000 00000000 00000000 00000000  ......
000002ac: 00000000 00000000 00000000 01111101 10111010 11110011  ...}..
000002b2: 10101010 01000000 00000000 00000000 01100000 10111110  .@..`.
000002b8: 00000000 00001101 11110111 01101011 01101001 01110100  ...kit
000002be: 01110100 01111001 00000000 00000000 00000000 11011011  ty....
000002c4: 10011000 01111000 11001000 01011000 00000001 00000000  .x.X..
000002ca: 11100000 01000010 01111110 01001010 01011011 00010110  .B~J[.
000002d0: 00100000 01010011 00000001 00000000 00000001 00000000   S....
000002d6: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000002dc: 00000000 00000000 00000001 00000000 00000000 00000000  ......
000002e2: 11000001 01010001 11001011 10100111 11000000 00000000  .Q....
000002e8: 00000000 00000000 00000000 00000000 00010010 11111101  ......
000002ee: 01100010 01110010 01100101 01100001 01110100 01101000  breath
000002f4: 00000000 00000000 00110010 10110100 00111101 01001001  ..2.=I
000002fa: 01100001 00000000 00000000                             a..

预期 output：

00000000: 10111011 10011110 00000011 00000000 00000000 00000000  ......
00000006: 00000000 00000000 00000000 01111110 01111110 10011101  ...~~.
0000000c: 10111010 00001011 00000000 00000000 00000001 00000001  ......
00000012: 00000000 10110001 00001101 00000000 00000000 00000000  ......
00000018: 00000000 00000000 00000000 00111000 00111111 11010110  ...8?.
0000001e: 11100110 11111000 11001011 00000001 00101110 10000110  ......
00000024: 01110100 01100101 01101110 01110100 00000000 00000000  tent..
0000002a: 00000000 00000000 00000000 00000000 10000000 00111111  .....?
00000030: 01000101 00001011 00000000 00000001 00000000 00000000  E.....
00000036: 00000000 00000000 00000000 00000000 00000000 00000000  ......
0000003c: 10111111 00000001 00000000 00000000 00000000 00000001  ......
00000042: 00000000 00000000 00000001 00000000 10110001 00001110  ......
00000048: 00000000 00000000 00000000 01001101 00110110 01110001  ...M6q
0000004e: 10101001 01000000 10101101 11010110 11110111 11001011  .@....
00000054: 00000001 11011010 01001010 01100110 01110010 01100001  ..Jfra
0000005a: 01101101 01100101 00000000 00000000 00000000 01010000  me...P
00000060: 10111011 10100001 01000100 01010100 11101010 01100001  ..DT.a
00000066: 10101011 01001000 00001001 11110110 10000010 11100001  .H....
0000006c: 11010000 10000001 00000001 10001111 00000000 00000000  ......
00000072: 00000000 00000000 00000001 00000000 00000000 00000001  ......
00000078: 00000000 10001011 11110011 00000000 00000000 00000000  ......
0000007e: 00000000 00000000 00000000 00000000 00000000 11001110  ......
00000084: 10001000 10000110 11001011 00000000 00110101 01101011  ....5k
0000008a: 01100011 01101111 01110010 01101011 00000000 00000000  cork..
00000090: 00000000 00000000 00000000 00000000 10000000 00111111  .....?
00000096: 01001100 00000000 00000000 01100000 10000000 00110111  L..`.7
0000009c: 10001110 00110100 11000101 00100000 10111010 00000001  .4. ..
000000a2: 00000001 10000011 11000100 10110110 11101000 00000000  ......
000000a8: 00000000 00000000 00000000 00000000 01101011 10111011  ....k.
000000ae: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000000b4: 00000000 00000000 00000000 00000000 11011100 10111111  ......
000000ba: 00000001 00000001 00000000 01101001 01110011 01101100  ...isl
000000c0: 01100001 01101110 01100100 00000000 00000000 00000000  and...
000000c6: 00000000 00000000 00000000 01101010 00000001 00000000  ...j..
000000cc: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000000d2: 00000000 00000000 00000001 10111001 10100100 00100100  .....$
000000d8: 00100001 11111101 00000001 00000000 00000001 00000000  !.....
000000de: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000000e4: 01111101 10111010 11110011 10101010 01000000 00000000  }...@.
000000ea: 00000000 01100000 10111110 00000000 00001101 11110111  .`....
000000f0: 01101011 01101001 01110100 01110100 01111001 00000000  kitty.
000000f6: 00000000 00000000 11011011 10011000 01111000 11001000  ....x.
000000fc: 01011000 00000001 00000000 11100000 01000010 01111110  X...B~
00000102: 01001010 01011011 00010110 00100000 01010011 00000001  J[. S.
00000108: 00000000 00000001 00000000 00000000 00000000 00000000  ......
0000010e: 00000000 00000000 00000000 00000000 00000000 00000001  ......
00000114: 00000000 00000000 00000000 11000001 01010001 11001011  ....Q.
0000011a: 10100111 11000000 00000000 00000000 00000000 00000000  ......
00000120: 00000000 00010010 11111101 01100010 01110010 01100101  ...bre
00000126: 01100001 01110100 01101000 00000000 00000000 00110010  ath..2
0000012c: 10110100 00111101 01001001 01100001 00000000 00000000  .=Ia..
00000132: 11010011 11110011 11101100 01010110 00000101 10011000  ...V..
00000138: 10010110 00000001 00000000 00000001 11000100 10000001  ......
0000013e: 00011110 00000000 00000000 00000000 00000000 00000001  ......
00000144: 00000000 11100101 00000000 00000000 00000000 00000000  ......
0000014a: 00000000 00000000 00000000 11110000 00111111 00000000  ....?.
00000150: 00000000 00000000 00000000 00000000 10001101 10111010  ......
00000156: 01110111 01101000 01100101 01100101 01101100 00000000  wheel.
0000015c: 00000000 00000000 10110011 11100111 00010110 11001001  ......
00000162: 01001001 00001000 00000000 00000001 00000000 00000000  I.....
00000168: 00000000 00000000 00000000 00000000 00000000 00000000  ......
0000016e: 00011000 11111110 00111000 00000000 00000000 00000001  ..8...
00000174: 00000000 00000000 00000001 00000000 00001010 00000000  ......
0000017a: 00000000 00000000 10000000 01110000 11011001 10111110  ...p..
00000180: 10100110 01000000 00000000 00000000 00000000 00000000  .@....
00000186: 00000001 00000001 00000000 01100101 01100111 01100111  ...egg
0000018c: 01101110 01101111 01100111 00000000 00000000 00110100  nog..4
00000192: 01110001 00100011 01001001 01010111 00011111 01001111  q#IW.O
00000198: 00000001 00000000 00000000 00000000 00000000 00000000  ......
0000019e: 00000000 00000000 00000001 01100111 00000000 00000000  ...g..
000001a4: 00000000 00000000 00000000 00000000 00000001 00000001  ......
000001aa: 00000000 00001010 11100111 00000000 00000000 00000000  ......
000001b0: 00000000 00000000 00000000 11110000 00111111 00000000  ....?.
000001b6: 00000000 10000000 00111111 00000001 00000000 00000000  ..?...
000001bc: 01100010 01100001 01110011 01101011 01100101 01110100  basket
000001c2: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000001c8: 01001111 10101111 00000001 01111011 11001110 00000011  O..{..
000001ce: 00101001 10000111 10110011 01101011 01110111 00000000  )..kw.
000001d4: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000001da: 00000000 00000001 00000001 00000000 00000001 00000000  ......
000001e0: 00000000 00000000 10000000 01011101 10000110 11011011  ...]..
000001e6: 10100101 11000000 00000000 00000000 10000000 00111111  .....?
000001ec: 00000000 00000000 00000000 01110011 01101111 01100011  ...soc
000001f2: 01101001 01100101 01110100 01111001 00000000 10011001  iety..
000001f8: 11110000 01110000 11001001 01010111 11100011 11000001  .p.W..
000001fe: 01011001 11111000 11111111 11111111 11111111 11111111  Y.....
00000204: 11111111 11111111 00000000 00000001 00000001 00000000  ......
0000020a: 00000000 00000000 00000001 00000000 00000000 00000000  ......
00000210: 00000000 00000001 00000000 00000000 00000000 00000000  ......
00000216: 00000000 00000000 00000000 11101000 10111110 00000000  ......
0000021c: 00000000 10000000 00111111 00000001 10010001 10011010  ..?...
00000222: 01110100 01101111 01110101 01100011 01101000 00000000  touch.
00000228: 00000000 00000000 10011111 10101011 00010100 01001001  .....I
0000022e: 01111101 00000000 00000000 00000000 00000000 00000000  }.....
00000234: 00000000 00000000 00000000 00000000 00000000 00000000  ......
0000023a: 11011110 10100100 11101010 01011010 00000000 00000000  ...Z..
00000240: 00000000 00000000 00000001 00000000 00000000 00000000  ......
00000246: 00000000 00000000 00000000 00000000 00000000 00000000  ......
0000024c: 00000000 00000000 11000000 00000011 01111001 01001000  ....yH
00000252: 00000000 00000001 00000000 01101101 01100001 01110000  ...map
00000258: 00000000 00000000 00000000 00000000 00000000 00000000  ......
0000025e: 00000000 00000000 00000000 00111010 00001110 00000000  ...:..
00000264: 10011111 00000011 01010000 11011111 01010110 11111010  ..P.V.
0000026a: 01011101 01110011 00000001 11010111 00001111 00111110  ]s...>
00000270: 00000000 00000000 00000000 00000000 00000001 00000001  ......
00000276: 00000000 00000000 00000000 00000000 00000000 00000000  ......
0000027c: 10000000 00111110 11000111 00100010 01000000 01111100  .>."@|
00000282: 00110100 10010000 01001011 00000000 00011000 11111110  4.K...
00000288: 01110011 01100011 01101000 01101111 01101111 01101100  school
0000028e: 00000000 00000000 00000000 00000000 10000000 00111111  .....?
00000294: 01001100 01000111 10111000 10111110 11010110 10101111  LG....
0000029a: 01011100 00001111 11110101 10111000 10010111 00000000  \.....
000002a0: 00000000 01100000 01011001 00010011 00001001 00000000  .`Y...
000002a6: 00000000 00000000 00000000 00000000 00010110 00001011  ......
000002ac: 00000000 00000000 10000000 01111101 11011000 10011001  ...}..
000002b2: 10100000 11000000 11001000 00110101 11000101 01001011  ...5.K
000002b8: 00000001 00000000 00000000 01110110 01100101 01110011  ...ves
000002be: 01110100 00000000 00000000 00000000 00000000 11101111  t.....
000002c4: 00101011 00110111 11001001 01111110 01110010 10100001  +7.~r.
000002ca: 00000000 00000000 00000000 00000000 00000000 00000000  ......
000002d0: 00000000 00000000 00000000 01101100 00100101 10111110  ...l%.
000002d6: 01001101 10111010 00000001 00000000 00000001 00000000  M.....
000002dc: 00000000 00000001 00000000 00000000 00000000 00000000  ......
000002e2: 00000000 00000000 00000000 11110000 00111111 01000000  ....?@
000002e8: 11111100 11001001 01001011 00000000 10011000 01000100  ..K..D
000002ee: 01100110 01101001 01110011 01101000 00000000 00000000  fish..
000002f4: 00000000 00000000 00000000 00000000 00111101 10111110  ....=.
000002fa: 01100011 00000001 00000000                             c..

1 个解决方案

解决方案1
 0  2022-08-31 16:08:21

有多个问题。

首先，您的标题表明您应从二进制文件中读取结构。

您正在单独阅读结构的每个成员。 这不是任务声明告诉您的内容，但从查看文件内容来看，它似乎是正确的，因为文件中似乎没有填充。

感谢@Ian Abbott 指出这一点。

但是您以错误的顺序阅读它们。 您必须遵守它们在结构中定义的顺序。

然后你用错误的 arguments 调用qsort ：

您必须传递数组元素的大小。 该值用于计算每个元素在 memory 中的位置。 您将指针的大小传递给数组。

更正后的调用将是

  qsort(testDatabase, records, sizeof(*testDatabase), cmp);

最后，您的任务还告诉您使用指针数组。 这可能是因为交换指针比交换大型结构更省力。 您没有使用指针数组。

与该问题无关的其他一些错误：

FILE * fptr = fopen(argv[1], "rb");

在检查argc >1之前使用argv[1] 。 在检查它是否为NULL之前，您还可以使用fptr 。

固定版本可能如下所示。 没有测试...

int main(int argc, char *argv[]) {

    if (argc <= 1 || argc >= 4) {  //check if there are parameters
        usage();
        return 0;
    }

    FILE * fptr = fopen(argv[1], "rb");
    if (fptr == NULL) {    //check if file exists or not
        fprintf(stderr, "No such file or directory %s\n", argv[1]);
        exit(1);
    }

    size_t fileLength;
    fseek(fptr, 0, SEEK_END);
    fileLength = ftell(fptr);
    fseek(fptr, 0, SEEK_SET);

    size_t records = fileLength/STRUCTSIZE;
    
    database *FileData = malloc(sizeof(*FileData) * records);
    database **SortArray = malloc(sizeof(*SortArray) * records));

    // Read the file
    for (size_t i = 0; i < records; i++) {            
        fread(&FileData[i].organization, sizeof(FileData[i]->organization), 1, fptr);
        // TODO: Check return value
        // << Read all the other fields ...
    }
    fclose(fptr);

    // Create array of pointers into that array
    for (size_t i = 0; i < records; i++)
    {
      SortArray[i] = &fileData[i];
    }
    

    /* sorting */
    qsort(SortArray, records, sizeof(*SortArray), cmp);
    
    /* writing */
    FILE * output = fopen(argv[2], "wb");
    // TODO: Check return value

    for (size_t i = 0; i < records; i++)
    {
        fwrite(&SortArray[i]->organization, sizeof(SortArray[i]->organization), 1, output);
        // TODO: Check return value
        // << Write all the other fields ...
    }
    fclose(output);

    /* release memory */
    free(SortArray);
    free(FileData);

    return 0;
}

然后，您必须调整您的cmp function 以将参数解释为database**而不是database*

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