coder

#include <stdio.h>

int Encoder(char fname1[], char fname2[], char key[]){
    FILE *fp; FILE *fk;
    if(fname1 == NULL || fname2 == NULL || key == 0) return -2;
    int skey = 0, k = 0;
    char val = 0;
    while(key[skey] != 13) skey++;
    if ((fp = fopen(fname1, "r")) == NULL)
    {
        getchar();
        return -1;
    }
    if ((fk = fopen(fname2, "w")) == NULL)
    {
        getchar();
        return -1;
    }


    while(fscanf(fp, "%c", &val) != EOF){
        fprintf(fk, "%c", val^key[k]);
        if(k == skey - 1) k = 0;
        else k++;
    }
    fclose(fp);
    fclose(fk);
    return 0;
}


int LegitCheck(char fname1[], char fname2[])
{
    FILE *fp; FILE *fk;
    if ((fp = fopen(fname1, "r")) == NULL)
    {
        getchar();
        return -1;
    }
    if ((fk = fopen(fname2, "r")) == NULL)
    {
        getchar();
        return -1;
    }
    char val1 = 0, val2 = 0;
    while(fscanf(fp, "%c", &val1) != EOF && fscanf(fk, "%c", &val2) != EOF){
        if(val1 != val2) return 0;
    }
    if(fscanf(fp, "%c", &val1) != EOF || fscanf(fk, "%c", &val2) != EOF) return 0;
    return 1;
}


int main(){
    int m1 = Encoder("file1.txt", "file2.txt", "");
    if(m1 == -1){
        printf("Unable to execute.\n");
        return 0;
    }
    if(m1 == -2){
        printf("Input error.\n");
        return 0;
    }
    int m2 = Encoder("file2.txt", "file3.txt", "");
    if(m2 == -1){
        printf("Unable to execute.\n");
        return 0;
    }
    if(m2 == -2){
        printf("Input error.\n");
        return 0;
    }
    printf("%d\n", LegitCheck("file1.txt", "file3.txt"));


    return 0;
}