C语言小练习-1

1.打印乘法口诀表

#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<stdlib.h>
int main()
{
	int i = 0;
	int j = 0;
	for (i = 1; i < 10; ++i)
	{
		for (j = 1; j <= i; ++j)
		{
			printf("%d*%d=%d ", i, j, i*j);
		}
		printf("\n");
	}
	system("pause");
	return 0;
}

2.判断闰年

#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<stdlib.h>
int main()
{
	int year = 0;
	int flag = 1;
	while (flag)
	{
		printf("请输入年份：");
		scanf("%d", &year);
		if (year < 0)
		{
			printf("输入错误，请重新输入：");
			continue;
		}
		else
		{
			if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0))
			{
				printf("\n%d年是闰年。\n", year);
			}
			else printf("\n%d年不是闰年。\n", year);
		}
		printf("\n是否继续输入(1.是 0.否)：");
		scanf("%d", &flag);
	}
	system("pause");
	return 0;
}