计算器，结果输出后，输入Y或N，决定进入下一次计算还是退出程序

[mko_y]

/*
计算器，让用户选择输入y或者Y，以执行另一个计算，输入N或n就结束程序
*/

#include  <stdio.h>
#include <ctype.h>
int main(void)
{
	double number2,number1;
	char operation;
	char x;	
    
select1 :
	{printf("Input number1 operation number2!");
	scanf("%lf %c %lf",&number1,&operation,&number2);

	switch (operation)
	{
	case '+':
		printf("%.2lf %c %.2lf = %.2lf",number1,operation,number2,number2+number1);
		printf("Would u need another calculation?y for yes, and N for NO!\n");
		scanf("%c",&x);
		if (toupper(x)=='Y')
		{
			goto select1;

		}
		else break;
	case '-':
		printf("%.2lf %c %.2lf = %.2lf\n",number1,operation,number2,number2+number1);
		printf("Would u need another calculation?y for yes, and N for NO!\n");
		scanf("%c",&x);
		if (toupper(x)=='Y')
		{
			goto select1;
			
		}
		else break;
	case '/':
		if (number2==0)
		{
			printf("Sorry!iput the right number!");
			break;
		}
		else
     	printf("%.2lf %c %.2lf = %.2lf\n",number1,operation,number2,number1/number2);
		printf("Would u need another calculation?y for yes, and N for NO!\n");
		scanf("%c",&x);
		if (toupper(x)=='Y')
		{
			goto select1;
			
		}
		else break;
	case '*':
		printf("%.2lf %c %.2lf = %.2lf\n",number1,operation,number2,number1*number2);
		printf("Would u need another calculation?y for yes, and N for NO!\n");
		scanf("%c",&x);
		if (toupper(x)=='Y')
		{
			goto select1;
			
		}
		else break;

	}
	}
	
	
	return 0;
}

运行结果：
-----------------------------
Input number1 operation number2!
1+2
1.00 + 2.00 = 3.00
Would u need another calculation?y for yes, and N for NO!
Press any key to continue
-------------------------------------
此时键入任何信息，都退出窗体，
请高人赐教，如何调整？
为什么会直接出现Press any key to continue
这个是怎么回事出现的？

[面包大师]

select1 :
	{printf("Input number1 operation number2!");
	scanf("%lf %c %lf",&number1,&operation,&number2);
	getchar();//在这儿加个这个就好了

[luciferisnotsatan]

scanf("%c",&x);前清下缓冲看看fflush( stdin );

[c_losed]

#include  <stdio.h>
#include <ctype.h>
int main(void)
{
	double number2,number1;
	char operation;
	char x;    

select1 :
	{printf("Input number1 operation number2!\n");
	scanf("%lf %c %lf",&number1,&operation,&number2);
	fflush(stdin);//刷新下
	switch (operation)
	{
	case '+':
		printf("%.2lf %c %.2lf = %.2lf",number1,operation,number2,number2+number1);
		printf("Would u need another calculation?y for yes, and N for NO!\n");
		scanf("%c",&x);
		if (toupper(x)=='Y')
		{
			goto select1;

		}
		else break;
	case '-':
		printf("%.2lf %c %.2lf = %.2lf\n",number1,operation,number2,number2+number1);
		printf("Would u need another calculation?y for yes, and N for NO!\n");
		scanf("%c",&x);
		if (toupper(x)=='Y')
		{
			goto select1;

		}
		else break;
	case '/':
		if (number2==0)
		{
			printf("Sorry!iput the right number!");
			break;
		}
		else
			printf("%.2lf %c %.2lf = %.2lf\n",number1,operation,number2,number1/number2);
		printf("Would u need another calculation?y for yes, and N for NO!\n");
		scanf("%c",&x);
		if (toupper(x)=='Y')
		{
			goto select1;

		}
		else break;
	case '*':
		printf("%.2lf %c %.2lf = %.2lf\n",number1,operation,number2,number1*number2);
		printf("Would u need another calculation?y for yes, and N for NO!\n");
		scanf("%c",&x);
		if (toupper(x)=='Y')
		{
			goto select1;

		}
		else break;

	}
	}


	return 0;
}

[面包大师]

要清除输入缓冲区，不然会自动运行的。。。

[面包大师]

但由MSDN上的fflush定义：
If the file associated with stream is open for output, fflush writes to that file the contents of the buffer associated with the stream. If the stream is open for input, fflush clears the contents of the buffer.

[面包大师]

由以上可见fflush(stdin)在VC上还是有效地！鉴于各编译器对fflush的未定义行为实现不一样，不推荐使用fflush(stdin)刷新输入缓冲区。

[xuxinmmy]

#include <stdio.h>
#include <ctype.h>
int main(void)
{
double number2,number1;
char operation;
char x;

select1 :
printf("Input number1 operation number2!\n");
scanf("%lf %c %lf",&number1,&operation,&number2);

switch (operation)
{
case '+':
printf("%.2lf %c %.2lf = %.2lf\n",number1,operation,number2,number1+number2);
break;
case '-':
printf("%.2lf %c %.2lf = %.2lf\n",number1,operation,number2,number1-number2);
break;
case '/':
if (number2==0)
{
printf("Sorry!iput the right number!\n");
}
else
{
printf("%.2lf %c %.2lf = %.2lf\n",number1,operation,number2,number1/number2);
}
break;
case '*':
printf("%.2lf %c %.2lf = %.2lf\n",number1,operation,number2,number1*number2);
break;
default:
break;

}
printf("Would u need another calculation?\ny for yes, and N for NO!\n");

while(true)
{
x = getchar();
if('y' == x || 'Y' == x)
{
goto select1;
}
else if('n' == x || 'N' == x)
{
break;
}
}


return 0;
}

[flowingfirefly]

[Quote=引用 1 楼 czh3642210 的回复:]

C/C++ code
select1 :
{printf("Input number1 operation number2!");
scanf("%lf %c %lf",&number1,&operation,&number2);
getchar();//在这儿加个这个就好了
[/Quote]
这个方法行，简单而且行之有效。

[mko_y]

[Quote=引用 1 楼 czh3642210 的回复:]

C/C++ code
select1 :
{printf("Input number1 operation number2!");
scanf("%lf %c %lf",&number1,&operation,&number2);
getchar();//在这儿加个这个就好了
[/Quote]

是诶，加上ok了,请问是什么原理啊， 我看不懂啊

[mko_y]

[Quote=引用 2 楼 luciferisnotsatan 的回复:]

scanf("%c",&x);前清下缓冲看看fflush( stdin );
[/Quote]

您好fflush(stdin),fflush 是刷新的意思， 那stdin 是什么意思啊

[luciferisnotsatan]

stdin 是标准输入流

[面包大师]

getchar();//是用来清空输入缓冲区的，因为你上次输入的时候，有回车等字符，所以，你getchar一下就清空了，否则你直接scanf的话，就会获取到以前残留的

[mko_y]

[Quote=引用 12 楼 czh3642210 的回复:]

getchar();//是用来清空输入缓冲区的，因为你上次输入的时候，有回车等字符，所以，你getchar一下就清空了，否则你直接scanf的话，就会获取到以前残留的
[/Quote]

那流程应该是怎么样的啊，我想是：
比如 1+2
应该执行case ‘+’：

	case '+':
		printf("%.2lf %c %.2lf = %.2lf\n",number1,operation,number2,number2+number1);
		printf("Would u need another calculation?y for yes, and N for NO!\n");
	
		scanf("%c",&x);
		if (toupper(x)=='Y')
		{
			goto select1;

		}
		else break;

输出输出 然后再输入， 那和getchar（），那怎么会回到getchar（）啊

[面包大师]

只要在你上次输入和这次输入之间getchar()一下就好

[cougar0709]

getchar，神奇。。。

[mko_y]

[Quote=引用 14 楼 czh3642210 的回复:]

只要在你上次输入和这次输入之间getchar()一下就好
[/Quote]

谢谢了！
十分感谢！