C++ Program to Convert Binary to Hexadecimal

In this article, you will learn and get code on binary to hexadecimal conversion in C++. The program is created with and without using user-defined function.

But before going through program, if you are not aware about the steps and formula used for binary to hexadecimal conversion, then you can go there to get every required things.

Binary to Hexadecimal in C++

To convert binary number to hexadecimal in C++ programming, you have to ask from user to enter any number in binary number system. Then convert it into its equivalent hexadecimal value. Print the hexadecimal value as output.

The question is, write a program in C++, to receive any binary number and prints its equivalent hexadecimal value. The answer to this question is given below:

#include<iostream>
using namespace std;
int main()
{
    int binaryNum, hex=0, mul=1, chk=1, rem, i=0;
    char hexDecNum[20];
    cout<<"Enter any Binary Number: ";
    cin>>binaryNum;
    while(binaryNum!=0)
    {
        rem = binaryNum%10;
        hex = hex + (rem*mul);
        if(chk%4==0)
        {
            if(hex<10)
                hexDecNum[i] = hex+48;
            else
                hexDecNum[i] = hex+55;
            mul = 1;
            hex = 0;
            chk = 1;
            i++;
        }
        else
        {
            mul = mul*2;
            chk++;
        }
        binaryNum = binaryNum/10;
    }
    if(chk!=1)
        hexDecNum[i] = hex+48;
    if(chk==1)
        i--;
    cout<<"\nEquivalent Value in Hexadecimal: ";
    for(i=i; i>=0; i--)
        cout<<hexDecNum[i];
    cout<<endl;
    return 0;
}

This program was build and run under Code::Blocks IDE. Here is its sample run:

Now supply the binary number input say 1101110 and press ENTER key to its equivalent hexadecimal value as shown in the snapshot given below:

Here is another sample run with user input as 1010:

The dry run (of above program) with user input 1010 goes like:

• Initial values, hex=0, mul=1, chk=1, i=0
• When user enters 1010 as binary input, then 1010 gets initialized to binaryNum So binaryNum=1010
• Now the condition of while loop, binaryNum!=0 or 1010!=0 evaluates to be true. Therefore program flow goes inside the loop
• binaryNum%10 or 1010%10 or 0 gets initialized to rem. So rem=0
• hex+(rem*mul) or 0+(0*1) or 0 gets initialized to hex. So hex=0
• Now the condition of if statement, that is, chk%4==0 or 1%4==0 evaluates to be false. Therefore program flow does not goes inside the if's body, rather it goes to else's body
• And mul*2 or 1*2 or 2 gets initialized to mul. Now mul=2
• And then the value of chk gets incremented. Now chk=2
• And at last (last statement of while loop's body), binaryNum/10 or 1010/10 or 101 gets initialized to binaryNum. Now binaryNum=101
• Now program flow goes back and evaluates the condition of while loop again with new value of binaryNum. Again the condition 101!=0 evaluates to be true. Therefore, again program flow goes inside the loop
• Process the code until the condition of while loop evaluates to be false.
• On continuing the process, here are the values we'll get after each evaluation of while loop:
  • After first evaluation
    rem=0, hex=0, mul=2, chk=2, binaryNum=101
  • After second evaluation
    rem=1, hex=2, mul=4, chk=3, binaryNum=10
  • After third evaluation
    rem=0, hex=2, mul=8, chk=4, binaryNum=1
  • After fourth evaluation, this time the condition of if statement, that is, chk%4==0 or 4%4==0 or 0==0 evaluates to be true
    rem=1, hex=0, hexDecNum[0]=A, mul=1, chk=1, i=1, binaryNum=0
• Now after fourth evaluation, the value of binaryNum is 0. So the condition binaryNum!=0 or 0!=0 evaluates to be false. Therefore program flow does not goes inside the loop this time. It means, the evaluation of while loop gets ended
• Now the condition of if (after while loop, not inside), chk!=1 or 1!=1 evaluates to be false
• Now the program flow goes to next if's condition, and evaluates its condition, that is chk==1 or 1==1 evaluates to be true. So the value of i gets decremented. Now i=0
• Using for loop, that starts from the value of i and continues until its value becomes equal to 0, print the value hexDecNum[] one by one
• Because the value of i is 0, therefore the loop only evaluates at once. So value of hexDecNum[0] gets printed, that equals A

Using user-defined Function

Here is another program that also converts any binary number entered by user at run-time into its equivalent hexadecimal value, but using a user-defined function BinaryToHexaDec().

#include<iostream>
using namespace std;

void BinaryToHexaDec(int bin);
int i=0;
char hexDecNum[20];
int main()
{
    int binaryNum;
    cout<<"Enter any Binary Number: ";
    cin>>binaryNum;
    BinaryToHexaDec(binaryNum);
    cout<<"\nEquivalent Value in Hexadecimal: ";
    for(i=i; i>=0; i--)
        cout<<hexDecNum[i];
    cout<<endl;
    return 0;
}
void BinaryToHexaDec(int bin)
{
    int hex=0, mul=1, chk=1, rem;
    while(bin!=0)
    {
        rem = bin%10;
        hex = hex + (rem*mul);
        if(chk%4==0)
        {
            if(hex<10)
                hexDecNum[i] = hex+48;
            else
                hexDecNum[i] = hex+55;
            mul = 1;
            hex = 0;
            chk = 1;
            i++;
        }
        else
        {
            mul = mul*2;
            chk++;
        }
        bin = bin/10;
    }
    if(chk!=1)
        hexDecNum[i] = hex+48;
    if(chk==1)
        i--;
}

This program will produce the same output as of previous program.

Same Program in Other Languages

• C Binary to Hexadecimal
• Java Binary to Hexadecimal
• Python Binary to Hexadecimal

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