【C语言】switch应用：输入一个月份，输出2018年该月份有多少天

代码如下

//输入一个月份，输出2018年该月有多少天
#include <stdio.h>
int main(){
    
    
	int month,day;
	printf("Please enter the month number:");
	scanf("%d",&month);
	putchar('\n');
	switch(month){
    
    
		case 1:
		case 3:
		case 5:
		case 7:
		case 8:
		case 10:
		case 12: day=31; break;
		case 4:
		case 6:
		case 9:
		case 11: day=30; break;
		case 2: day=28; break;
		default: day=-1; break; 
	}
	if(day==-1){
    
    
		printf("Invalid  month input！\n");
	}
	else
		printf("The yeay of 2018 %d month has %d days！\n",month,day);
		
	return 0;
} 

测试输出