Simple C++ program to convert binary decimal number

Cpp Tutorial Contains

• Binary to Decimal Conversion Code in C++
  
• Program Logic Explanation
• Dry run the code with a simple input so the basic working of program can be understand easily

Concept Used

• Know the basic math of converting one number to other number e.g BINARY to DECIMAL
• functions 
• while loop

Problem Statement
Write a C++ program which asks user to input a binary number then convert it into its equivalent decimal number and show the result. 
To improve readability of program make a separate function and function should return the resultant number.

C++ CODE
Compiler used: C++ codeBlocks Compiler

#include<iostream>
using namespace std;
long ConvertBinary2Decimal(unsigned long num);
int main()

{
    unsigned long binary_num, decimal = 0;
    cout <<"\n\tEnter a binary number to get 
    Equivalent Decimal : ";
    cin >> binary_num;
    decimal=ConvertBinary2Decimal(binary_num);
    cout <<"\n\tDecimal Value Of  
   " <<binary_num << " is = " << decimal << endl;
    return 0;

}

long ConvertBinary2Decimal(unsigned long bin_num)
{
    unsigned long decimal = 0;
    int remainder=0, base = 1;


    while (bin_num > 0)

    {
        remainder = bin_num % 10;
        decimal = decimal + remainder * base;
        bin_num = bin_num / 10;
        base = base * 2;
    }

return decimal;

}

Program Explanation

• In main function user enters input number
• Calls the function and pass the number 
• Function calculates the required result and return
• In main function program displays the final result

Dry Run of Code

Input = 101

--------------------------------

Iteration     = 1

 remainder  = 1

 decimal     = 1

 bin_num   = 10

 base          =  2

--------------------------------

Iteration     = 2

 remainder  = 0

 decimal     = 1

 bin_num   = 1

 base          =  4

--------------------------------

Iteration     = 3

 remainder  = 1 -> as 1 mod 10 =1

 decimal     = 5 -> previous value+remainder*base = 5 RESULT

 bin_num   =  0

 base          =  8

--------------------------------

Main logic of the program in while loop take another input and dry run it into a notebook. Best of Luck

See another example here

convert decimal to binary