求两个整数最大公约数的欧几里德算法和求幂运算程序

求两个数最大公约数的欧几里德算法：

/*
*Author: gyh
*Date: 201412227
*Version: 1.0
*/
#include<stdio.h>
int gcd(int a, int b);
int main(void){
int a, b;
printf("Entry two numbers: ");
scanf("%d%d", &a, &b);
printf(" %d and %d's gcd is %d\n", a, b, gcd(a, b));
return 0;
}

int gcd(int a, int b){
int temp;
while( b != 0){
temp = a % b;
a = b;
b = temp;
}
return a;
}

求一个整数的正整数次幂运算：
/*
*Author: gyh
*Date: 20141227
*Version: 1.0
*/
#include<stdio.h>

long pow_(long x, unsigned int n);
int main(void){
long x;
unsigned int n;
printf("Entry the base number and exponent: ");
scanf("%ld%d", &x, &n);
printf("%ld pow %d is %ld\n", x, n, pow_(x, n));
return 0;
}

long pow_(long x, unsigned int n){
if(n == 0){
return 1;
}
if(n == 1){
return x;
}
if(n % 2 != 0){
return pow_(x * x, n/2) * x;
}else{
return pow_(x * x, n/2);
}
}