A programe to convert binary into decimal using Function.

#include<conio.h>

#include<stdio.h>

 void  convert(int );

void main()

{

int num;

printf("Enter a binary number(1s and 0s) \n");

scanf("%d", &num);

convert(num);                                                                         

getch();

}

 void  convert(int num )

{

int binary_val, decimal_val = 0, base = 1, rem;

binary_val = num;

while (num > 0)

{

rem = num % 10;

decimal_val = decimal_val + rem * base;

 num = num / 10 ;

base = base * 2;

 }

 printf("The Binary number is = %d \n", binary_val);

 printf("Its decimal equivalent is = %d \n", decimal_val);

 }
 

Output

Enter a binary number(1s and 0s)
100
The Binary number is = 100
Its decimal equivalent is =  4