#include<stdio.h>
int add(int x, int y)
{
    
    
	return x + y;
}
int sub(int x, int y)
{
    
    
	return x - y;
}
int mul(int x, int y)
{
    
    
	return x * y;
}
int div(int x, int y)
{
    
    
	return x / y;
}
void menu()
{
    
    
	printf("1.加、2.减、3.乘、4.除、0.退出\n");
}
int main()
{
    
    
	int input = 0;
	int x = 0;
	int y = 0;
	int (*p[5])(int, int) = {
    
     0,add,sub,mul,div };
	do {
    
    
		menu();
		printf("请选择：");
		scanf("%d", &input);
		if (input>=1&&input<=4)
		{
    
    
			printf("请输入两个数字：");
			scanf("%d%d", &x, &y);
			int ret = p[input](x, y);
			printf("%d\n", ret);
		}
		else if (input==0)
		{
    
    
			printf("退出。");
		}
		else
		{
    
    
			printf("输入有误。");
		}

	} while (input);

	return 0;
}