Bitwise XOR on unsigned char is terminating program without error

Question

I'm trying to create a 64 bit integer as class in C++, I know this already exists in the C header stdint.h but I thought it could be a fun challenge.

Anyway, I am trying to perform a bitwise XOR operation on three unsigned chars, and the program keeps stopping without warning, it just pauses for a split second and then stops:

unsigned char* a = (unsigned char*) 1;
unsigned char* b = (unsigned char*) 2;
unsigned char* c = (unsigned char*) 3;

unsigned char* result = (unsigned char*) malloc(sizeof(unsigned char));

std::cout << "Trying" << std::endl;
*result = *a ^ *b ^ *c;
std::cout << "Done!" << std::endl;

The output being:

PS C:\Users\super\Desktop> ./test.exe
Trying
PS C:\Users\super\Desktop>

I am using Windows 10 if that helps, let me know if you need any other information, and thanks for any help you can give me :)

Answer 1

You're trying to dereference invalid pointers. You want to get rid of a lot of those *s.

unsigned char a = 1;
unsigned char b = 2;
unsigned char c = 3;

unsigned char* result = (unsigned char*) malloc(sizeof(unsigned char));

std::cout << "Trying" << std::endl;
*result = a ^ b ^ c;
std::cout << "Done!" << std::endl;

Why are you allocating a single byte (sizeof(unsigned char) is 1 by definition) on the heap for the result? You could just make that another unsigned char variable, too.

Editorial note: you also don't need to use std::endl.