arranjo/combinacao/fatorial

#include<stdio.h>
#include<stdlib.h>
float fatorial(int n);
float arranjo(int n, int k);
float combinacao(int n, int k);
int main(void)
{
int n,k;
float fat,arr,comb;
printf("digite o valor de n,k\n");
scanf("%d %d",&n,&k);
fat=fatorial(n);
printf("fatorial de %d eh %f\n",n,fat);
arr=arranjo(n,k);
printf("arranjo de %d,%d eh %f\n",n,k,arr);
comb=combinacao(n,k);
printf("combinacao de %d,%d eh %f\n",n,k,comb);
system("pause");
return 0;
}
float fatorial(int n)
{
float f=1.0;
int i;
for(i=1;i<=n;i++)
{
f=f*i;
}
return f;
}
float arranjo(int n, int k)
{
float a;
a=fatorial(n)/fatorial(n-k);
return a;
}
float combinacao(int n, int k)
{
float c;
c=fatorial(n)/(fatorial(k)*fatorial(n-k));
return c;
}