Valgrind错误

Question

我已经为rpn计算器编写了一个代码，该代码从文件中获取输入。

该代码似乎适用于我的测试用例，但Valgrind告诉我有28个错误。 我是C语言的新手，我不太用Valgrind。 我不明白这些错误是什么。 有人可以帮我了解它们是什么以及如何修复它们吗？

没有内存泄漏。

这是我的代码，非常混乱的代码。

#include <stdio.h>
#include <stdlib.h>
#include<string.h>


float rpn (char * filename)
{ 

 float result;

   FILE *in = fopen(filename, "r");
if (in == NULL)
  {
    fprintf(stderr," input file fopen fail\n");
    return EXIT_FAILURE;  // if fopen fails, return false
  }       

int count=0;
char c;

 for (c = getc(in); c != EOF && c!='\n'; c = getc(in))
  { 
    if(c==' ')
     {
       count = count + 1;
     }  
 } 
 fclose(in);

 if (count==0)
 {
  fprintf(stderr,"EMPTY FILE\n");
  fclose(in);
  return EXIT_SUCCESS;
}


 fprintf(stderr,"count=%d\n",count);


 FILE *in2 = fopen(filename, "r");
 if (in == NULL)
   {
     fprintf(stderr," input file fopen fail\n");
     return EXIT_FAILURE;  // if fopen fails, return false
   }             
   int num = 0;
   int num_op = 0;
   int index =0;
   int len = count+1;

    fprintf(stderr,"len = %d\n",len);

    char**input = malloc(sizeof(char*)*(len+1));

    for(int i =0;i<len; i++)
     { 

        input[i] = malloc(sizeof(char));  

        fscanf(in2,"%s",input[i]);




          if((strcmp(input[i],"+")==0)||(strcmp(input[i],"-")==0)||(strcmp(input[i],"*")==0)||(strcmp(input[i],"/")==0))  
     {
       num_op = num_op + 1;
     }
  else if(atof(input[i])||(strcmp(input[i],"0")==0)||(strcmp(input[i],"-0")==0))
     { 
       index = index+1;
       num = num+1;
     }
   }
  fclose(in2);  

fprintf(stderr,"numbers= %d\n",num);
fprintf(stderr,"num_op= %d\n",num_op);
fprintf(stderr,"index= %d\n",index);

if((num != (num_op+1)))
{
 fprintf(stderr,"Bad Input\n");
  return EXIT_FAILURE;
}

for (int f=index;f<len;f++)
 { 
    if(!((strcmp(input[f],"+")==0)||(strcmp(input[f],"-")==0)||(strcmp(input[f],"*")==0)||(strcmp(input[f],"/")==0)))
      {
        fprintf(stderr,"Bad Input\n");
        return EXIT_FAILURE;
      }
 }  



float *stack = malloc(sizeof(float)*(index+1));

for(int h=0; h<index; h++)
  {
     stack[h] = atof(input[h]);
  }

   /*   for(int l =0;(l<index); l++)
  {
    printf("stack[%d] = %lf\n",l,stack[l]); 
 }      




for(int j =0;(j<len); j++)
   {
   printf("input[%d] = %s\n",j,input[j]);
   }
 */



   int u = index-1;
   for(int k=index;k<len;k++)
     { 
       if ((strcmp(input[k],"+"))==0)
         {

               stack[u-1] = (stack[u-1] + stack[u]);
               printf("Result + = %lf\n",stack[u-1]);
         }         

    else if ((strcmp(input[k],"-"))==0)
      {   
               stack[u-1] = (stack[u-1] - stack[u]);
               printf("Result -  = %lf\n",stack[u-1]);
      }
  else if ((strcmp(input[k],"*"))==0)  
      {
               stack[u-1] = (stack[u-1] * stack[u]);
                printf("Result *  = %lf\n",stack[u-1]);
      }    

    else if ((strcmp(input[k],"/"))==0)
    { 
               stack[u-1] = (stack[u-1] / stack[u]);
                printf("Result /  = %lf\n",stack[u-1]);
     }  

      else{
                printf("Invalid Operator\n");

                return EXIT_FAILURE;
           }


                  if ((u) == 1)
                  {
                     printf("stack_last= %lf\n",stack[u-1]);
                     result = stack[u-1];
                     for(int d =0;d<len; d++)
                        { 

                          free(input[d]);
                        }

                    free(input);
                    free(stack);
                    return result;

                  }
               u = u-1;
     }



  return EXIT_FAILURE;


   }
   int main (int argc, char ** argv) {
     if (argc != 2) {
    fprintf(stderr, "Incorrect number of arguments.\n");
    fprintf(stderr, "Usage: ./pa11 <input file>\n");        
    return EXIT_FAILURE;

                   }

   float result; //store the result of your calculation here.

  result=(rpn(argv[1]));

fprintf(stdout,"Result = %f\n", result);

return EXIT_SUCCESS;
  }

这些是valgrind的错误

==7692== Invalid write of size 1
==7692==    at 0x391C858C76: _IO_vfscanf (vfscanf.c:1110)
==7692==    by 0x391C8645EA: __isoc99_fscanf (isoc99_fscanf.c:35)
==7692==    by 0x401320: rpn (pa11.c:70)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e5b1 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
==7692== Invalid read of size 1
==7692==    at 0x391C83AC70: ____strtod_l_internal (strtod_l.c:732)
==7692==    by 0x401411: rpn (pa11.c:79)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e5b1 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
==7692== Invalid read of size 1
==7692==    at 0x391C83A478: ____strtod_l_internal (strtod_l.c:787)
==7692==    by 0x401411: rpn (pa11.c:79)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e5b1 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
==7692== Invalid write of size 1
==7692==    at 0x391C858257: _IO_vfscanf (vfscanf.c:1031)
==7692==    by 0x391C8645EA: __isoc99_fscanf (isoc99_fscanf.c:35)
==7692==    by 0x401320: rpn (pa11.c:70)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e601 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
==7692== Invalid read of size 1
==7692==    at 0x391C839E30: str_to_mpn (strtod_l.c:327)
==7692==    by 0x391C83B3D2: ____strtod_l_internal (strtod_l.c:1115)
==7692==    by 0x401411: rpn (pa11.c:79)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e601 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
==7692== Invalid read of size 1
==7692==    at 0x4A084E8: strcmp (mc_replace_strmem.c:729)
==7692==    by 0x40133D: rpn (pa11.c:75)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e6a1 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
==7692== Invalid read of size 1
==7692==    at 0x4A084E8: strcmp (mc_replace_strmem.c:729)
==7692==    by 0x401374: rpn (pa11.c:75)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e6f1 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
numbers= 3
num_op= 2
index= 3
==7692== Invalid read of size 1
==7692==    at 0x4A084E8: strcmp (mc_replace_strmem.c:729)
==7692==    by 0x401619: rpn (pa11.c:99)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e6a1 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
==7692== Invalid read of size 1
==7692==    at 0x4A084E8: strcmp (mc_replace_strmem.c:729)
==7692==    by 0x401650: rpn (pa11.c:99)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e6f1 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
==7692== Invalid read of size 1
==7692==    at 0x391C83AC70: ____strtod_l_internal (strtod_l.c:732)
==7692==    by 0x40177B: rpn (pa11.c:112)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e5b1 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
==7692== Invalid read of size 1
==7692==    at 0x391C83A478: ____strtod_l_internal (strtod_l.c:787)
==7692==    by 0x40177B: rpn (pa11.c:112)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e5b1 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
==7692== Invalid read of size 1
==7692==    at 0x391C839E30: str_to_mpn (strtod_l.c:327)
==7692==    by 0x391C83B3D2: ____strtod_l_internal (strtod_l.c:1115)
==7692==    by 0x40177B: rpn (pa11.c:112)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e601 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
==7692== Invalid read of size 1
==7692==    at 0x4A084E8: strcmp (mc_replace_strmem.c:729)
==7692==    by 0x4017E8: rpn (pa11.c:134)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e6a1 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
Result + = 12.000000
==7692== Invalid read of size 1
==7692==    at 0x4A084E8: strcmp (mc_replace_strmem.c:729)
==7692==    by 0x40187C: rpn (pa11.c:141)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692==  Address 0x4c3e6f1 is 0 bytes after a block of size 1 alloc'd
==7692==    at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==7692==    by 0x4012F4: rpn (pa11.c:68)
==7692==    by 0x401CAD: main (pa11.c:199)
==7692== 
Result -  = -5.000000
stack_last= -5.000000
Result = -5.000000
==7692== 
==7692== HEAP SUMMARY:
==7692==     in use at exit: 0 bytes in 0 blocks
==7692==   total heap usage: 10 allocs, 10 frees, 1,773 bytes allocated
==7692== 
==7692== All heap blocks were freed -- no leaks are possible
==7692== 
==7692== For counts of detected and suppressed errors, rerun with: -v
==7692== ERROR SUMMARY: 28 errors from 14 contexts (suppressed: 6 from 6)

Answer 1

显然您在这里有错误：

    input[i] = malloc(sizeof(char));  

    fscanf(in2,"%s",input[i]);

如果要输入一个char ，则需要使用%c而不是%s ，对于%s您需要分配至少两个char ，一个用于符号，另一个用于尾随'\\0'