# C Program For Convert Binary Number to Decimal or Decimal Number to Binary Using Function

#include <stdio.h>
#include <math.h>
int bin_to_dec(int n);
int dec_to_bin(int n);
int main()
{
int n;
char c;
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, bin_to_dec(n));
}
if (c =='b' || c == 'B')
{
printf("Enter a decimal number: ");
scanf("%d", &n);
printf("%d in decimal = %d in binary", n, dec_to_bin(n));
}
return 0;
}

int dec_to_bin(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 bin_to_dec(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;
}

Output:-

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#### post written by: Ghanendra Yadav

Hi, I’m Ghanendra Yadav, SEO Expert, Professional Blogger, Programmer, and UI Developer. Get a Solution of More Than 500+ Programming Problems, and Practice All Programs in C, C++, and Java Languages. Get a Competitive Website Solution also Ie. Hackerrank Solutions and Geeksforgeeks Solutions. If You Are Interested to Learn a C Programming Language and You Don't Have Experience in Any Programming, You Should Start with a C Programming Language, Read: List of Format Specifiers in C.