目录

while循环展示

for循环展示

do...while循环

题目

while循环展示

int main()
{
	//
	char password[20] = { 0 };
	printf("请输入密码:>");
	scanf("%s", password);//123456
	//gets
	printf("请确认密码(Y/N):>");
	//清理缓冲区
	//getchar();//处理'n'
	// 
	//清理缓冲区的中多个字符
	int tmp = 0;
	while ((tmp = getchar()) != 'n')
	{
		;
	}

	int ch = getchar();
	if (ch == 'Y')
	{
		printf("确认成功n");
	}
	else
	{
		printf("确认失败n");
	}
	return 0;
}

（getchar输出是整形）

for循环展示

写for循环建议左闭右开，如：

for(i=1;i<10;i++)

此时10即为循环次数

 

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do...while循环

例：

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题目 计算n的阶乘

//算阶乘
int main()
{
	int i;
	int j = 1;
	int sum = 1;
	scanf("%d", &i);

	while (j <=i)
	{
		sum = sum * j;
		j = j + 1;
	}
	printf("%d", sum);


	return 0;
}

计算1！+2！+3!.......+i!

例1：

int main()
{
	int i;
	int j = 1;
	int a = 1;
	int sum = 1;
	int result = 0;

	scanf("%d",&i);
	while (j <= i)
	{
		while (a <= j)
		{
			sum = sum * a;
			a = a + 1;
		}
		j = j + 1;
		result = result + sum;
	}
	printf("%d", result);
	return 0;
}

例2：

int main()
{
	int n;
	int sum = 0;
	int result = 1;
	int x;
	scanf("%d", &x);
	for (n = 1;n <= x;n++)
	{
		result = result * n;
		sum = sum + result;

	} 
	printf("%d", sum);
}

 

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