How to convert Hexadecimal to Binary in C++

 Conversion of Hexadecimal to Binary

Each Hexadecimal digit has a corresponding binary value. Converting hexadecimal to binary is as simple as writing each hexadecimal digit binary correspondent.

To write the binary correspondent we follow the 8421 rule. (8421 rule)

So as per this rule, the hexadecimal digits are converted to binary as follows:

PROGRAM:

#include <bits/stdc++.h>
using namespace std;

void HexToBin(string hexdec)
{
    long int  i = 0;
 
     while(hexdec[i]!='\0')
  {
 
        switch (hexdec[i]) 
    {
        case '0':
            cout << "0000";
            break;
        case '1':
            cout << "0001";
            break;
        case '2':
            cout << "0010";
            break;
        case '3':
            cout << "0011";
            break;
        case '4':
            cout << "0100";
            break;
        case '5':
            cout << "0101";
            break;
        case '6':
            cout << "0110";
            break;
        case '7':
            cout << "0111";
            break;
        case '8':
            cout << "1000";
            break;
        case '9':
            cout << "1001";
            break;
        case 'A':
        case 'a':
            cout << "1010";
            break;
        case 'B':
        case 'b':
            cout << "1011";
            break;
        case 'C':
        case 'c':
            cout << "1100";
            break;
        case 'D':
        case 'd':
            cout << "1101";
            break;
        case 'E':
        case 'e':
            cout << "1110";
            break;
        case 'F':
        case 'f':
            cout << "1111";
            break;
        default:
            cout << "\nInvalid hexadecimal digit "<< hexdec[i];
            exit(0);
        }//switch
        i++;
    }//while
}//hexa
 
int   main()
{
    char hexdec[100] ;
    cout<<"\nEnter a valid Hexadecimal numeric value:";
    cin>>hexdec;
    cout << "\nEquivalent Binary value is : ";
    HexToBin(hexdec);
    return 0;
 
    
}//main

OUTPUT