C Program to Convert Binary Number to Decimal and vice-versa

#include <stdio.h>

#include<conio.h>

#include <math.h>

int binary_decimal(int n);

int decimal_binary(int n);

void main()

{

   int n;

   char c;

   clrscr();

   printf("Instructions:\n");

   printf("1. Enter alphabet 'd' to convert binary to decimal.\n");

   printf("2. Enter alphabet 'b' to convert decimal to binary.\n");

   scanf("%c",&c);

   if (c =='d' || c == 'D')

   {

       printf("Enter a binary number: ");

       scanf("%d", &n);

       printf("%d in binary = %d in decimal", n, binary_decimal(n));

   }

   if (c =='b' || c == 'B')

   {

       printf("Enter a decimal number: ");

       scanf("%d", &n);

       printf("%d in decimal = %d in binary", n, decimal_binary(n));

   }

   getch();

}

int decimal_binary(int n)  /* Function to convert decimal to binary.*/

{

    int rem, i=1, binary=0;

    while (n!=0)

    {

        rem=n%2;

        n/=2;

        binary+=rem*i;

        i*=10;

    }

    return binary;

}

int binary_decimal(int n) /* Function to convert binary to decimal.*/

{

    int decimal=0, i=0, rem;

    while (n!=0)

    {

        rem = n%10;

        n/=10;

        decimal += rem*pow(2,i);

        ++i;

    }

    return decimal;

}