从文本文件中读取，并使用每一行进行比较，看看它们是否是字谜

Question

I must modify my program to accept input from a file called anagrams.txt.This file should have two strings per line, separated by the # character. My program should read each pair of strings and report back if each pair of strings is an anagram. For example consider the following content of anagrams.txt:

hello#elloh
man#nam
Astro#Oastrrasd

Your program should print out the following:

hello#elloh - Anagrams!

man#nam - Anagrams!

Astro#Oastrrasd- Not anagrams!

I should compile in g++

Here is the code to read from text:

int main()
{
    char input[30];




      if(access( "anagrams.txt", F_OK ) != -1)           {

            FILE *ptr_file;
        char buf[1000];

        ptr_file =fopen("anagrams.txt","r");     if (!ptr_file)
            return 1;

        while (fgets(buf,1000, ptr_file)!=NULL)
            printf("%s",buf);

    fclose(ptr_file);
        printf("\n");
      }

      else{ //if file does not exist
        printf("\nFile not found!\n");
      }


        return 0;
}

Code to find if the text are anagrams:

 #include <stdio.h>

int find_anagram(char [], char []);

int main()
{
    char array1[100], array2[100];
    int flag;

    printf("Enter the string\n");
    gets(array1);
    printf("Enter another string\n");
    gets(array2);
    flag = find_anagram(array1, array2);
    if (flag == 1)
        printf(" %s and %s are anagrams.\n", array1, array2);
    else
        printf("%s and %s are not anagrams.\n", array1, array2);
    return 0;
}

int find_anagram(char array1[], char array2[])
{
    int num1[26] = {0}, num2[26] = {0}, i = 0;

    while (array1[i] != '\0')
    {
        num1[array1[i] - 'a']++;
        i++;
    }
    i = 0;
    while (array2[i] != '\0')
    {
        num2[array2[i] -'a']++;
        i++;
    }
    for (i = 0; i < 26; i++)
    {
        if (num1[i] != num2[i])
            return 0;
    }
    return 1;
}

Answer 1

Since this looks like a University question, I won't provide a full solution, only a hint.

All you have to do is replace the stdin input part of the anagram-finding file with the code you wrote to read from a file: it's as simple as changing

printf("Enter the string\n");
gets(array1);
printf("Enter another string\n");
gets(array2);

to // before program: #define SIZE 1000

// inside main

if (access("anagrams.txt", F_OK) == -1){
    printf("\nFile not found!\n");
    return 1; // Abort the program early if we can't find the file
}
FILE *ptr_file;
char buf[1000];

ptr_file = fopen("anagrams.txt","r");
if (!ptr_file)
    return 1;

char array1[SIZE], array2[SIZE];

while (fgets(buf, 1000, ptr_file)!=NULL){
    // do all your anagram stuff here!
    // there is currently one line of the input file stored in buf

    // Hint: You need to split buf into array_1 and array_2 using '#' to separate it.

}


fclose(ptr_file);
printf("\n");

Additional comments:

1. Don't ever ever ever use gets . gets doesn't check that the string it writes to can hold the data, which will cause your program to crash if it gets input bigger than the array size. Use fgets(buf, BUF_SIZE, stdin) instead.
2. Beautiful code is good code. People are more likely to help if they can read your code easily. (fix your brackets)
3. Just for interest, a more efficient algorithm for checking anagrams is to use qsort to sort both arrays, then a simple string matcher to compare them. This will have cost O(mnlog(m+n)) , as opposed to O(m^2 n^2) , awith the current algorithm

Answer 2

You need to split every line you read by fgets (as you did) in to two strings, and pass them to your find_anagram function. You can do that using strtok :

int main()
{
  int flag;
  char buf[1000];
  FILE *ptr_file;

  //Check file existence

  //Open the file for reading

  while (fgets (buf, 1000, ptr_file) != NULL)
    {
      char *array1 = strtok(buf, "#");
      char *array2 = strtok(NULL, "\n");

      flag = find_anagram (array1, array2);

      //Check flag value to print your message
    }

  return 0;
}

//put your find_anagram function

Don't forget to #include <string.h> to use strtok() .

Answer 3

You can try something like this:

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

#define MAXLINE 1000
#define MAXLETTER 256

int is_anagram(char *word1, char *word2);
void check_lines(FILE *filename);
int cmpfunc(const void *a, const void *b);
void convert_to_lowercase(char *word);

int
main(int argc, char const *argv[]) {
    FILE *filename;

    if ((filename = fopen("anagram.txt", "r")) == NULL) {
        fprintf(stderr, "Error opening file\n");
        exit(EXIT_FAILURE);
    }

    check_lines(filename);

    fclose(filename);

    return 0;
}

void
check_lines(FILE *filename) {
    char line[MAXLINE];
    char *word1, *word2, *copy1, *copy2;

    while (fgets(line, MAXLINE, filename) != NULL) {
        word1 = strtok(line, "#");
        word2 = strtok(NULL, "\n");

        copy1 = strdup(word1);
        copy2 = strdup(word2);

        convert_to_lowercase(copy1);
        convert_to_lowercase(copy2);

        if (is_anagram(copy1, copy2)) {
            printf("%s#%s - Anagrams!\n", word1, word2);
        } else {
            printf("%s#%s - Not Anagrams!\n", word1, word2);
        }
    }
}

void
convert_to_lowercase(char *word) {
    int i;

    for (i = 0; word[i] != '\0'; i++) {
        word[i] = tolower(word[i]);
    }
}

int
is_anagram(char *word1, char *word2) {

    qsort(word1, strlen(word1), sizeof(*word1), cmpfunc);
    qsort(word2, strlen(word2), sizeof(*word2), cmpfunc);

    if (strcmp(word1, word2) == 0) {
        return 1;
    } 
    return 0;
}

int
cmpfunc(const void *a, const void *b) {
    if ((*(char*)a) < (*(char*)b)) {
        return -1;
    }

    if ((*(char*)a) > (*(char*)b)) {
        return +1;
    }

    return 0;
}