Method 1
#include<stdio.h>
#include<conio.h>
#include<math.h>
void bin_dec(long int num) // Function Definition
{
long int rem,sum=0,power=0;
while(num>0)
{
rem = num%10;
num = num/10;
sum = sum + rem * pow(2,power);
power++;
}
printf("Decimal number : %d",sum);
}
void main()
{
long int num;
clrscr();
printf("Enter the Binary number (0 and 1): ");
scanf("%ld",&num);
bin_dec(num);
getch();
}Output
Enter the Binary number : 111
Decimal number : 7