How to read and recognize arrow key taken as an input in c/c++

[surajgyl]

I am facing this problem from last 2-3 days , i have searched about it but couldn't get the help.
I want to know that how can we take arrow keys as an input and then how can we recognize them that whether the key is "UPARROW" or "DOWNARROW" or "RIGHTARROW" or "LEFTARROW".

plz provide some help....... i will be thankful

[manasij7479]

i have searched about it but couldn't get the help.

Did you ?
I see better results : Let me google that for you

[surajgyl]

Did you ?
I see better results : Let me google that for you

Sir will u plz help me out to understand this code.

[surajgyl]

The code is:-

#include<iostream.h>

#include<conio.h>
#include<dos.h>

int main()
{
clrscr();
int ch;
while(1)
{
ch=getch();
if(ch==0)
{
ch=getch();
if(ch==72) cout<<"up";
else if(ch==75) cout<<"left";
else if(ch==77) cout<<"right";
else if(ch==80) cout<<"down";
cout<<endl;
}
else break;
}
delay(2000);
return 0;
}

[QuantumPete]

...and your question now is?

[surajgyl]

...and your question now is?

Sir,
the question is, how do we compare these keys. i mean i know everykey has an ascii value, and the source code i have mentioned above is comparing ascii values of arrow keys as "72,75,77 and 80" but according to my knowledge 72 is the ascii value of "H", and that is my question, how we can compare those keys ???

[surajgyl]

no solution

[memcpy]

Don't double post. There's an "edit" button for a reason.

Also, the source code you found/posted is terrible. It isn't standard C (cout?), it uses all outdated headers, and, as you said, the value of the arrow keys isn't represented by 72, 75, 77, and 80.

I wrote a quick test (note: WON'T WORK IF NOT *NIX) to determine the *real* value of the escape codes that represented an arrow:

	int ch, i;
	struct termios term;
	
	tcgetattr( STDIN_FILENO, &term );
	term.c_lflag &= ~( ICANON | ECHO );
	tcsetattr( STDIN_FILENO, TCSANOW, &term );
	
	for (i = 0; i < 4; i++) {
		puts("enter arrow");
		ch = getchar() & 0xFF;
		ch += getchar() & 0xFF;
		ch += getchar() & 0xFF;
		printf("%c | %d\n", ch, ch); 
	}

This took the (usually 3) characters that represent an arrow, and captured them all. The result:

enter arrow
? | 183
enter arrow
? | 184
enter arrow
? | 185
enter arrow
? | 186

In order: up, down, left, right.

[quzah]

It isn't standard C (cout?)

See: cout - C++ Reference


Quzah.