Question

Using the C programming language, write a program that takes in hexadecimal characters (using the fgets() function) and return a translated string of ASCII characters. Use only BITWISE operators, not arithmetic.

Answer 1

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

//function to convert from hexa to decimal
int hexaToDecimal(char c)
{
int first = c;
first = first >> 4;
first = first - 3;
int second = c;
second = second & 0x0F;
  
int decimal = (first<<1 + first<<3) + second;

if(decimal >= 10)
decimal--;
return decimal;
}

//fuction to convert from hexa to ascii
int hexaToASCII(char firstHexa, char secondHexa)
{
int highByte = hexaToDecimal(firstHexa) << 4;
int lowByte = hexaToDecimal(secondHexa);
return highByte | lowByte;
}

int main()
{
//variable declaration
char hexa[100];// = "41";
printf("Enter hex number: ");
fgets(hexa,sizeof(hexa),stdin);
  
//get string length
int strLength = strlen(hexa);
  
//display output
printf("\nThe equivalent ASCII string is: ");
for(int i = 0; i < strLength-1; i++)
{
printf("%c", hexaToASCII(hexa[i], hexa[i+1]));
i++;
}
}

OUTPUT: