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

char * xorencrypt (char * message, char * key) {
    size_t messagelen = strlen(message);
    size_t keylen = strlen(key);

    char * encrypted = malloc(messagelen+1);

    int i;
    for(i = 0; i < messagelen; i++) {
        encrypted[i] = message[i] ^ key[i % keylen];
    }
    encrypted[messagelen] = '\0';

    return encrypted;
}

char *readFile(char *fileName)
{
    FILE *file;
    char *code = malloc(1000 * sizeof(char));
    file = fopen(fileName, "r");
    do
    {
      *code++ = (char)fgetc(file);

    } while(*code != EOF);
    return code;
}

int main(int argc, char * argv[]) {
    char * message = readFile(argv[1]);
    char * key = readFile(argv[2]);

    char * encrypted = xorencrypt(message, key);
    printf("%s\n", encrypted);
    free(encrypted);

    return 0;
}