Question

Write a program in C that xor:s two numbers without using the built-in xor

bool xor_bit ( bool a , bool b ) {

// xor two bits , without using ^.

}

uint32_t xor_word ( uint32_t a , uint32_t b) {

// xor two words , without using ^; instead call xor_bit for every bit .

}

int main () {

uint_32 a = 0xaabbccdd ;

uint_32 b = 0 x11223344 ;

// xor a and b by calling xor_word

//Print out the result as a hexadecimal number

}

Answer 1

//C program

#include <stdio.h>
#include <stdbool.h>
#include <stdint.h>
bool xor_bit ( bool a , bool b ) {

   return (a & b) ? 0 : (a | b);

}

uint32_t xor_word ( uint32_t a , uint32_t b) {
   uint32_t result = 0;
   int i;
   for (i = 31; i >= 0; i--)
{

bool b1 = a & (1 << i);
bool b2 = b & (1 << i);

bool xoredBit = xor_bit ( b1 , b2 ) ;   
  
result <<= 1;
result |= xoredBit;
}
return result;

}

int main () {

uint32_t a = 0xaabbccdd ;

uint32_t b = 0x11223344 ;

uint32_t result = xor_word ( a , b);

printf("%x\n",result);

return 0;

}

//sample output