XOR-Encryption works on Code blocks not on Visual Studio 2017 - c

Question

so I would like to encrypt my data when write into .txt file so I choose XOR-Encryption from this code:
Github
So when I run in code blocks it runs and shows this result:
Encrypted: :=.43*-:8m2$.a
Decrypted:kylewbanks.com0
Process returned 0 (0x0) execution time : 0.025 s
Press any key to continue.
But When I start use Visual Studio 2017 it shows this error:
Error (active) E0059 function call is not allowed in a constant expression
Which means I cant put variable when declaring an array, so is there any method for my encryption to work in VS2017.
I think the problems is when declare the variable using constant, anyway to force it or other encryption method that is easy to use, I wont need to be secure just to prevent plain text in file.
Anyway this is the only code:
#include <stdio.h>
#include <string.h>
void encryptDecrypt(char *input, char *output) {
char key[] = {'K', 'C', 'Q'}; //Can be any chars, and any size array
int i;
for(i = 0; i < strlen(input); i++) {
output[i] = input[i] ^ key[i % (sizeof(key)/sizeof(char))];
}
}
int main () {
char baseStr[] = "kylewbanks.com";
char encrypted[strlen(baseStr)];
encryptDecrypt(baseStr, encrypted);
printf("Encrypted:%s\n", encrypted);
char decrypted[strlen(baseStr)];
encryptDecrypt(encrypted, decrypted);
printf("Decrypted:%s\n", decrypted);
}

Answer 1

MSVC does not support Variable Length Arrays. One way round is to allocate the memory.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void encryptDecrypt(char *input, char *output) {
char key[] = {'K', 'C', 'Q'}; //Can be any chars, and any size array
size_t i;
for(i = 0; i < strlen(input); i++) {
output[i] = input[i] ^ key[i % (sizeof(key)/sizeof(char))];
}
output[i] = '\0'; // terminate
}
int main () {
char baseStr[] = "kylewbanks.com";
size_t len = strlen(baseStr) + 1;
char *encrypted = malloc(len);
if(encrypted == NULL) {
// error handling
}
encryptDecrypt(baseStr, encrypted);
printf("Encrypted:%s\n", encrypted);
char *decrypted = malloc(len);
if(decrypted == NULL) {
// error handling
}
encryptDecrypt(encrypted, decrypted);
printf("Decrypted:%s\n", decrypted);
free(decrypted);
free(encrypted);
}
Please note that an extra byte is needed for the string terminator - and the string should be terminated.