处理非输入键击? [英] Handling non-input keystrokes?
问题描述
我不确定该如何表达我想问的内容；在C ++中，使用stdio.h标头而不是iostream，我如何做到这一点，以便在任何时候按下转义键都会终止程序?是否可以在程序顶部添加一次，还是必须将其分别添加到每个循环/条件循环中?下面是我的代码(sleep()函数仅用于视觉加载/计算效果):
I'm not sure exactly how to phrase what I'm trying to ask; in C++, using the stdio.h header instead of iostream, how would I make it so that if the escape key is pressed at any point, the program is terminated? Is there something I could add once at the top of the program, or would I have to add it to every loop/conditional individually? Below is my code (the sleep() function is just for a visual loading/calculating effect):
#include <stdio.h>
#include <math.h>
#include <windows.h>
void repeat();
void quadratic()
{
double a, b, c;
double ans[2];
printf("-Arrange your equation in the form aX^2+bX+c \n-Enter the value of a: ");
scanf("%lf", &a);
printf("-Enter the value of b: ");
scanf("%lf", &b);
printf("-Enter the value of c: ");
scanf("%lf", &c);
double radical=((b*b)-(4*a*c));
double root=sqrt(radical);
double negB=(-1)*b;
double denominator=2*a;
if(denominator==0)
{
printf("Calculating");
Sleep(100);
printf(".");
Sleep(100);
printf(".");
Sleep(100);
printf(".");
Sleep(100);
printf("\nError: Denominator must be non-zero.\n \n \n");
}
else if(radical==0)
{
ans[0]=negB/denominator;
printf("Both roots are equal: both values are X=%lf\n \n \n", ans[0]);
}
else if(radical<0)
{
printf("Calculating");
Sleep(100);
printf(".");
Sleep(100);
printf(".");
Sleep(100);
printf(".");
Sleep(100);
double r,i;
radical*=-1;
r=negB/(2*a);
i=sqrt(radical)/(2*a);
printf("\nBoth roots are imaginary numbers.\n");
printf("Non-real answer(s): X=%lf+%lfi X=%lf-%lfi\n \n \n",r,i,r,i);
}
else
{
ans[0]=(negB+root)/denominator;
ans[1]=(negB-root)/denominator;
printf("Calculating");
Sleep(100);
printf(".");
Sleep(100);
printf(".");
Sleep(100);
printf(".");
Sleep(100);
printf("\nX=%lf, X=%lf\n \n", ans[0], ans[1]);
}
repeat();
}
void repeat()
{
quadratic();
}
int main(void)
{
quadratic();
return 0;
}
推荐答案
我是否可以在程序顶部添加一次内容，还是必须将其分别添加到每个循环/条件中?em>
Is there something I could add once at the top of the program, or would I have to add it to every loop/conditional individually?
我认为您可以添加一次，然后在整个程序中使用它轻松捕获按键事件.
I think you can add something once, and use it to catch key stroke events easily throughout your program.
以下是一个代码段，显示了我用来在控制台应用程序中处理按键事件的功能.它使用 GetAsyncKeyState().包含的部分显示了如何捕获CTRL键，以及一旦看到后如何做某事.(所示的代码段显示了如何捕获< ctrl>< shift>< h> 键序列，以显示使用此特定例程的帮助菜单.
Following is a code snippet showing a function I have used to handle key stroke events in a console application. It uses GetAsyncKeyState(). Included is a section that shows how to capture a CTRL key, and how you can do something once you see it. (the snippet shown shows how I capture a <ctrl><shift><h> key sequence to display a help menu for using this particular routine.
注意: 在描述中， delay_x(浮动延迟)只是一个自定义的，非阻塞的睡眠或延迟功能，其中包括调用以下代码段.从主程序循环 while(1){...} 中调用它.按键组合之一提供了退出程序的方法:< CTRL>< SHIFT>< K>
Note: In the description, delay_x(float delay) is simply a custom, non-blocking sleep, or delay function that includes a call to the following snippet. It is called from within the main program loop while(1){...} . Exiting the program is provided in one of the keystroke combinations: <CTRL><SHIFT><K>
代码段:
Code snippet:
/////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////
//
// SetAppState() is called continuously from within delay_x()
// to capture keystroke combinations as they occur asynchronously
// with this application, Keystroke combinations are listed below
//
// Note: GetAsyncKeyState() can maintian information regarding the
// state of a key instantaineously by use the MSB,
// and recently by using the LSB.
//
// For this application
// only instantaineous information will be kept, minimizing
// conflicts with other keyboard shortcut definitions
// defined by other applications that may be running
// simultaineously.
//
/////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////
void SetAppState(void)
{
short state=0;
short state1=0;
state = GetAsyncKeyState(VK_CONTROL);
if (0x80000000 & state) //check instantaineous state of key
{
state = GetAsyncKeyState(VK_SHIFT);
if (0x80000000 & state) //check instantaineous state of key
{
state = GetAsyncKeyState('h');
state1 = GetAsyncKeyState('H');
if ((0x80000000 & state) ||
(0x80000000 & state1))
{ sprintf(gTempBuf, "Usage - keystrokes to access and control the PaAutoStartSlot application:\n\n"
"<CTRL><SHIFT> H (H)elp - \n"
"<CTRL><SHIFT> V o(V)erride - \n"
"<CTRL><SHIFT> S (S)tatus - \n"
"<CTRL><SHIFT> K (K)ill - \n"
"<CTRL><SHIFT> N (N)o - \n"
"<CTRL><SHIFT> I (I)Inside - \n"
"<CTRL><SHIFT> O (O)Outside- \n"
"\nSee log file at this location for runtime errors: \n\n%s", LOGFILE);
MessagePopup("Usage Menu",gTempBuf);
}
///// ... more code ...
End of snippet
编辑 -回答注释中的问题如何调用GetAsyncKeyState()
有很多方法可以同时调用 other 的 GetAsyncKeyState().线程是一个好方法.您也可以使用 while()/switch(){} 组合直接完成所有操作.这是一个非常简单的示例(使用伪代码)
There are many ways you could call GetAsyncKeyState() at the same time other stuff is going on. Threads are a good way. You can also do it all in line using a while()/switch(){} combination. Here is a very simple example of how you could do this (in pseudo code)
int gRunning = 1;
int state = 1;
int main(void)
{
//create variables, initialize stuff
while(gRunning)//this is your main program loop
{
delay_x(1.0);//check for keystrokes
switch(state) {
case 1:
//do some stuff here
//and experiment with values passed to delay_x(n)
delay_x(10000);//check for keystrokes
state++;
break;
case 2:
//do some different stuff here
delay_x(10000);//check for keystrokes
state++;
break;
... Add as many cases as you need for your program.
case n://last case, set execution flow to top
//do some more different stuff here
delay_x(10000);//check for keystrokes
state = 1;//loop back to top
break;
}
}
return 0;
}
void delay_x (float delay)
{
static clock_t time1;
static clock_t time2; clock();
time1 = clock();
time2 = clock();
while ((time2 - time1) < delay)
{
time2 = clock();
SetAppState(); //see partial definition in my original answer above.
}
}
注意: :使用此方法，您可以根据需要设置任意数量的 cases ，重要的是保持对 GetAsyncKeyState()的稳定调用.通过调用 delay_x().
Note: Using this method, you can have as many, or as few, cases as you need, the important thing is to keep a steady flow of calls to GetAsyncKeyState(). This does that via the call to delay_x().
注2: :以下是导致程序退出的段(添加到上面的定义中):
Note2: Here is the segment (added to above definition) that will cause your program to exit:
state = GetAsyncKeyState('k');
state1 = GetAsyncKeyState('K');
if ((0x80000000 & state) ||
(0x80000000 & state1))
{
printf("Kill Program");
gRunning = FALSE;
}
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