C :

#include <stdio.h>
int main(int argc, char *argv[])
{
	float fact(int n);
	int m,n,result;
	scanf("%d%d",&m,&n);
	result=fact(m)/(fact(n)*fact(m-n));
	printf("%d",result);
	return 0;
}
float fact(int n)
{
	float sum=1;
	for(;n>0;n--)
	{
		sum*=n;
	}
	return sum;
	
}

C++ :

#include<stdio.h>
int main()
{
	int i,j,k;
	long long sum;
	int  n,m;
	scanf("%d %d",&n,&m);
	sum=1;
	if(m>n/2)
	m=n-m;
	for(i=0;i<m;i++)
	{
		sum*=n-i;
		sum/=1+i;
	}
	printf("%lld\n",sum);
		
	
	return 0;
}