Write a c program to convert a binary numbers to equivalent decimal number. [WBUT MCA 2011]

#include <stdio.h>
#include <math.h>

int main()
{
	char nos[20];
	int i,fl=1,res=0,temp;
	printf("Enter A Numbers : ");
	gets(nos);
	//check for valid binary number
	for(i=0;nos[i]!='\0';i++)
	{
		//48 and 49 is the ascii code for 0 and 1 respectively
		if(nos[i] < 48 || nos[i] >  49)
		{
			fl=0;
			break;
		}
 	}
	if(fl)
	{
		strrev(nos);
		puts(nos);
		for(i=0;nos[i]!='\0';i++)
		{
			temp=nos[i]-48;
			res += temp * pow(2,i);
		}
		printf("Binary eqivalent of %s is %d",nos,res);
	}
	else
	{
		printf("!!! *** INVALID BINARY NUMBER *** !!!");
	}
}

Output

======

Enter A Numbers : 1011

Binary eqivalent of 1101 is 11