我从来都不记得我是怎么做到的，因为它很少出现在我身上。但是在C或c++中，从标准输入中读取字符而不等待换行符(按enter)的最佳方法是什么?
理想情况下，它也不会将输入字符回显到屏幕上。我只是想在不影响控制台屏幕的情况下捕捉击键。
当前回答
在WINDOWS上我这样做:
#include <Windows.h>
int main()
{
system("PAUSE>NUL");
if (GetKeyState(0x41/*(the 'A' key, choosen e.g.)*/) & (0xff80/*That stands for "Default state / Key Down"*/)) {
//whatever I want to do after 'A' is pressed
}
}
这里可以找到一个键的列表，每个键都有自己的十六进制值: https://learn.microsoft.com/en-us/windows/win32/inputdev/virtual-key-codes
其他回答
假设是Windows，看一下ReadConsoleInput函数。
在Linux(和其他类unix系统)上，这可以通过以下方式完成:
#include <unistd.h>
#include <termios.h>
char getch() {
char buf = 0;
struct termios old = {0};
if (tcgetattr(0, &old) < 0)
perror("tcsetattr()");
old.c_lflag &= ~ICANON;
old.c_lflag &= ~ECHO;
old.c_cc[VMIN] = 1;
old.c_cc[VTIME] = 0;
if (tcsetattr(0, TCSANOW, &old) < 0)
perror("tcsetattr ICANON");
if (read(0, &buf, 1) < 0)
perror ("read()");
old.c_lflag |= ICANON;
old.c_lflag |= ECHO;
if (tcsetattr(0, TCSADRAIN, &old) < 0)
perror ("tcsetattr ~ICANON");
return (buf);
}
基本上你必须关闭规范模式(和回声模式来抑制回声)。
由于这里之前的解决方案不能跨平台工作，并且在特殊键上存在问题，所以这里是我的解决方案，它在Windows和Linux上都可以工作，并且使用了最少的外部库(Windows.h和Linux的sys/ioctl.h+termios.h)。
对于ASCII字符(换行符/tab/space/backspace/delete， !"#$%&'()*+，-./0-9:;<=>?@A-Z[]^_ ' a-z{|}~üäÄöÖÜßµ´§°¹³)，返回ASCII码(正数);对于特殊键(方向键、上页/下页、pos1/end、转义、插入、F1-F12)，返回Windows虚拟键码(负数)的负数。
#include <iostream>
#include <string>
#include <thread> // contains <chrono>
using namespace std;
void println(const string& s="") {
cout << s << endl;
}
void sleep(const double t) {
if(t>0.0) this_thread::sleep_for(chrono::milliseconds((int)(1E3*t+0.5)));
}
// ASCII codes (key>0): 8 backspace, 9 tab, 10 newline, 27 escape, 127 delete, !"#$%&'()*+,-./0-9:;<=>?@A-Z[]^_`a-z{|}~üäÄöÖÜßµ´§°¹³²
// control key codes (key<0): -38/-40/-37/-39 up/down/left/right arrow, -33/-34 page up/down, -36/-35 pos1/end
// other key codes (key<0): -45 insert, -144 num lock, -20 caps lock, -91 windows key, -93 kontext menu key, -112 to -123 F1 to F12
// not working: ¹ (251), num lock (-144), caps lock (-20), windows key (-91), kontext menu key (-93), F11 (-122)
#if defined(_WIN32)
#define WIN32_LEAN_AND_MEAN
#define VC_EXTRALEAN
#include <Windows.h>
int key_press() { // not working: F11 (-122, toggles fullscreen)
KEY_EVENT_RECORD keyevent;
INPUT_RECORD irec;
DWORD events;
while(true) {
ReadConsoleInput(GetStdHandle(STD_INPUT_HANDLE), &irec, 1, &events);
if(irec.EventType==KEY_EVENT&&((KEY_EVENT_RECORD&)irec.Event).bKeyDown) {
keyevent = (KEY_EVENT_RECORD&)irec.Event;
const int ca = (int)keyevent.uChar.AsciiChar;
const int cv = (int)keyevent.wVirtualKeyCode;
const int key = ca==0 ? -cv : ca+(ca>0?0:256);
switch(key) {
case -16: continue; // disable Shift
case -17: continue; // disable Ctrl / AltGr
case -18: continue; // disable Alt / AltGr
case -220: continue; // disable first detection of "^" key (not "^" symbol)
case -221: continue; // disable first detection of "`" key (not "`" symbol)
case -191: continue; // disable AltGr + "#"
case -52: continue; // disable AltGr + "4"
case -53: continue; // disable AltGr + "5"
case -54: continue; // disable AltGr + "6"
case -12: continue; // disable num block 5 with num lock deactivated
case 13: return 10; // enter
case -46: return 127; // delete
case -49: return 251; // ¹
case 0: continue;
case 1: continue; // disable Ctrl + a (selects all text)
case 2: continue; // disable Ctrl + b
case 3: continue; // disable Ctrl + c (terminates program)
case 4: continue; // disable Ctrl + d
case 5: continue; // disable Ctrl + e
case 6: continue; // disable Ctrl + f (opens search)
case 7: continue; // disable Ctrl + g
//case 8: continue; // disable Ctrl + h (ascii for backspace)
//case 9: continue; // disable Ctrl + i (ascii for tab)
case 10: continue; // disable Ctrl + j
case 11: continue; // disable Ctrl + k
case 12: continue; // disable Ctrl + l
//case 13: continue; // disable Ctrl + m (breaks console, ascii for new line)
case 14: continue; // disable Ctrl + n
case 15: continue; // disable Ctrl + o
case 16: continue; // disable Ctrl + p
case 17: continue; // disable Ctrl + q
case 18: continue; // disable Ctrl + r
case 19: continue; // disable Ctrl + s
case 20: continue; // disable Ctrl + t
case 21: continue; // disable Ctrl + u
case 22: continue; // disable Ctrl + v (inserts clipboard)
case 23: continue; // disable Ctrl + w
case 24: continue; // disable Ctrl + x
case 25: continue; // disable Ctrl + y
case 26: continue; // disable Ctrl + z
default: return key; // any other ASCII/virtual character
}
}
}
}
#elif defined(__linux__)
#include <sys/ioctl.h>
#include <termios.h>
int key_press() { // not working: ¹ (251), num lock (-144), caps lock (-20), windows key (-91), kontext menu key (-93)
struct termios term;
tcgetattr(0, &term);
while(true) {
term.c_lflag &= ~(ICANON|ECHO); // turn off line buffering and echoing
tcsetattr(0, TCSANOW, &term);
int nbbytes;
ioctl(0, FIONREAD, &nbbytes); // 0 is STDIN
while(!nbbytes) {
sleep(0.01);
fflush(stdout);
ioctl(0, FIONREAD, &nbbytes); // 0 is STDIN
}
int key = (int)getchar();
if(key==27||key==194||key==195) { // escape, 194/195 is escape for °ß´äöüÄÖÜ
key = (int)getchar();
if(key==91) { // [ following escape
key = (int)getchar(); // get code of next char after \e[
if(key==49) { // F5-F8
key = 62+(int)getchar(); // 53, 55-57
if(key==115) key++; // F5 code is too low by 1
getchar(); // take in following ~ (126), but discard code
} else if(key==50) { // insert or F9-F12
key = (int)getchar();
if(key==126) { // insert
key = 45;
} else { // F9-F12
key += 71; // 48, 49, 51, 52
if(key<121) key++; // F11 and F12 are too low by 1
getchar(); // take in following ~ (126), but discard code
}
} else if(key==51||key==53||key==54) { // delete, page up/down
getchar(); // take in following ~ (126), but discard code
}
} else if(key==79) { // F1-F4
key = 32+(int)getchar(); // 80-83
}
key = -key; // use negative numbers for escaped keys
}
term.c_lflag |= (ICANON|ECHO); // turn on line buffering and echoing
tcsetattr(0, TCSANOW, &term);
switch(key) {
case 127: return 8; // backspace
case -27: return 27; // escape
case -51: return 127; // delete
case -164: return 132; // ä
case -182: return 148; // ö
case -188: return 129; // ü
case -132: return 142; // Ä
case -150: return 153; // Ö
case -156: return 154; // Ü
case -159: return 225; // ß
case -181: return 230; // µ
case -167: return 245; // §
case -176: return 248; // °
case -178: return 253; // ²
case -179: return 252; // ³
case -180: return 239; // ´
case -65: return -38; // up arrow
case -66: return -40; // down arrow
case -68: return -37; // left arrow
case -67: return -39; // right arrow
case -53: return -33; // page up
case -54: return -34; // page down
case -72: return -36; // pos1
case -70: return -35; // end
case 0: continue;
case 1: continue; // disable Ctrl + a
case 2: continue; // disable Ctrl + b
case 3: continue; // disable Ctrl + c (terminates program)
case 4: continue; // disable Ctrl + d
case 5: continue; // disable Ctrl + e
case 6: continue; // disable Ctrl + f
case 7: continue; // disable Ctrl + g
case 8: continue; // disable Ctrl + h
//case 9: continue; // disable Ctrl + i (ascii for tab)
//case 10: continue; // disable Ctrl + j (ascii for new line)
case 11: continue; // disable Ctrl + k
case 12: continue; // disable Ctrl + l
case 13: continue; // disable Ctrl + m
case 14: continue; // disable Ctrl + n
case 15: continue; // disable Ctrl + o
case 16: continue; // disable Ctrl + p
case 17: continue; // disable Ctrl + q
case 18: continue; // disable Ctrl + r
case 19: continue; // disable Ctrl + s
case 20: continue; // disable Ctrl + t
case 21: continue; // disable Ctrl + u
case 22: continue; // disable Ctrl + v
case 23: continue; // disable Ctrl + w
case 24: continue; // disable Ctrl + x
case 25: continue; // disable Ctrl + y
case 26: continue; // disable Ctrl + z (terminates program)
default: return key; // any other ASCII character
}
}
}
#endif // Windows/Linux
最后，这里有一个如何使用它的例子:
int main() {
while(true) {
const int key = key_press(); // blocks until a key is pressed
println("Input is: "+to_string(key)+", \""+(char)key+"\"");
}
return 0;
}
CONIO.H
你需要的函数是:
int getch();
Prototype
int _getch(void);
Description
_getch obtains a character from stdin. Input is unbuffered, and this
routine will return as soon as a character is available without
waiting for a carriage return. The character is not echoed to stdout.
_getch bypasses the normal buffering done by getchar and getc. ungetc
cannot be used with _getch.
Synonym
Function: getch
int kbhit();
Description
Checks if a keyboard key has been pressed but not yet read.
Return Value
Returns a non-zero value if a key was pressed. Otherwise, returns 0.
libconio http://sourceforge.net/projects/libconio
or
conio.h的Linux c++实现 http://sourceforge.net/projects/linux-conioh
我也遇到过同样的问题。这里是一个小的解决方案为windows控制台使用cygwing++与if(GetKeyState(keycode) & bitANDcompare){};
#include <windows.h>
#include <fstream>
#include <iostream>
using namespace std;
void clear() {
COORD topLeft = { 0, 0 };
HANDLE console = GetStdHandle(STD_OUTPUT_HANDLE);
CONSOLE_SCREEN_BUFFER_INFO screen;
DWORD written;
GetConsoleScreenBufferInfo(console, &screen);
FillConsoleOutputCharacterA(
console, ' ', screen.dwSize.X * screen.dwSize.Y, topLeft, &written
);
FillConsoleOutputAttribute(
console, FOREGROUND_GREEN | FOREGROUND_RED | FOREGROUND_BLUE,
screen.dwSize.X * screen.dwSize.Y, topLeft, &written
);
SetConsoleCursorPosition(console, topLeft);
}
class Keyclick{
private:
int key;
char id;
public:
bool keydown = false;
Keyclick(int key1, char id1){
key=key1;
id=id1;
};
void watch(){
if(keydown==false){
if(GetKeyState(key) & 0x8000 ){
cout << id;
cout << " pressed.\r\n";
keydown = true;
}
}
if(keydown == true){
if(!(GetKeyState(key) & 0x8000)) {
cout << "released!!!!!!!!!!\r\n";
keydown = false;
clear();
}
}
};
};
int main()
{
bool primaryloop =true;
Keyclick keysp(VK_SPACE,'S');
Keyclick keyw(0x57,'w');
Keyclick keya(0x41,'a');
Keyclick keys(0x53,'s');
Keyclick keyd(0x44,'d');
Keyclick keyesc(VK_ESCAPE,'E');
while(primaryloop){
keysp.watch();
keyw.watch();
keya.watch();
keys.watch();
keyd.watch();
keyesc.watch();
if(keyesc.keydown){
primaryloop=false;
};
}
return 0;
}
https://github.com/wark77/windows_console_keypoller/blob/main/getkeystate_SOLUTION01.cpp
