Question

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

int main()
{
    int i = 0, len1=0, len2=0;
    int BUFSIZE = 1000;
    char* string1[20];
    char* string2[20];
    FILE *fp1 = fopen("input1.txt", "r");
    FILE *fp2 = fopen("input2.txt", "r");
    if ((fp1 == 0)||(fp2 == 0)){
        fprintf(stderr, "Error while opening");
        return 0;
    }
    string1[i] = (char*)malloc(BUFSIZE);
    string2[i] = (char*)malloc(BUFSIZE);
    while (fgets(string1[i], BUFSIZE, fp1)) {
        i++;
        len1+=strlen(string[i]);
        string1[i] = (char*)malloc(BUFSIZE);
        len1+=strlen(string1[i]);
    }

    i = 0;
    while (fgets(string2[i], BUFSIZE, fp2)) {
        i++;
        string2[i] = (char*)malloc(BUFSIZE);
    }

    printf("Output: \n");
    srand(time(NULL));
    int j = rand()%i;
    int k = (j+1)%i;
    fflush(stdout);
    printf("%d - %s %d -%s", j, string1[j], k, string1[k]);
    printf("%d - %s %d -%s", j, string2[j], k, string2[k]);
    printf("\n");
    printf("%d", len1);

    int x;
    for(x = 0; x<i; x++){
        free(string1[x]);
        free(string2[x]);
    }
    scanf("%d", x);
    fclose(fp1);
    fclose(fp2);
    return 0;
}

Thanks to user1807597’s help, I finally realize reading two strings and storing into arrays. But I still have trouble in getting the length of the array, I try to put len+=strlen(string[i]); in the while loop, but the compiler breaks when debugging. Someone knows why? Thank you!

Answer 1

I have modified the code.I think now it’s ok.You have wrong counting in the first while loop.And i++ should come after len1+=strlen(string[i]);.In the last scanf statement scanf("%d", x);,you have missed the operator ‘&’.

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

int main()
{
    int i = 0, len1 = 0, len2 = 0;
    int BUFSIZE = 1000;
    /*
       you have too  few lines here,
       If my file contains more than 20 lines,tragedy will occur!
       */
    char* string1[20];
    char* string2[20];

    FILE* fp1 = fopen("input1.txt", "r");
    FILE* fp2 = fopen("input2.txt", "r");

    if ((fp1 == 0) || (fp2 == 0))
    {
        fprintf(stderr, "Error while opening");
        return 0;
    }
    string1[i] = (char*)malloc(BUFSIZE);
    string2[i] = (char*)malloc(BUFSIZE);

    while (fgets(string1[i], BUFSIZE, fp1)!=NULL)
    {
        /*
        i++;
        */

        len1 += strlen(string1[i]);
        i++;
        string1[i] = (char*)malloc(BUFSIZE);
    }

    i = 0;
    while (fgets(string2[i], BUFSIZE, fp2))
    {
        i++;
        string2[i] = (char*)malloc(BUFSIZE);
    }

    printf("Output: \n");
    srand(time(NULL));
    int j = rand() % i;
    int k = (j + 1) % i;
    fflush(stdout);
    printf("%d - %s %d -%s", j, string1[j], k, string1[k]);
    printf("%d - %s %d -%s", j, string2[j], k, string2[k]);
    printf("\n");
    printf("%d", len1);

    int x;
    for (x = 0; x < i; x++)
    {
        free(string1[x]);
        free(string2[x]);
    }
    /*
    scanf("%d", x);
    */
    scanf("%d",&x);
    fclose(fp1);
    fclose(fp2);
    return 0;
}