I am trying to write a simple program that simulates a calculator. I would like the program to exit or turn-off when the Ctrl+D keystroke is made. I searched through stackoverflow and saw other examples of Ctrl+C or Ctrl+A but the examples are in java and C.
for C:
(scanf("%lf", &var);
for java, a SIGINT is raised when Ctrl+Z is pressed.
signal(SIGINT,leave);
for(;;) getchar();
I am wondering what can I do for Ctrl+D in C++...
Thanks everyone!
If you need to terminate with Ctrl-D while reading input.
while ( std::cin ) // Ctrl-D will terminate the loop
{
...
}
Ctrl+D will cause the stdin file descriptor to return end-of-file. Any input-reading function will reflect this, and you can then exit the program when you reach end-of-file. By the way, the C example should work verbatim in C++, though it may not be the most idiomatic C++.
Is this homework, by the way? If so, please be sure to tag it as such.
You could make life easier and scan for a keyword like "quit" or "exit". Last time I used a calculator, these words were not on the keypad.
Many simple calculator programs read the input as text terminated by a newline. They parse the text in memory, then spit out an answer.
Other more sophisticated calculator programs use windows and are event driven. Some use a button like "=" to signal end of input and start of calculation (doesn't work on RPN calculators).
These techniques remove the hassle of determining End Of Text input using a control character sequence and are more portable.
Under Unix, the terminal will interpret Ctrl+D (on an empty line) as the end of input; further reads from stdin will return EOF, which you can watch for.
Ctrl+D on Unixy platforms is EOF. If you are getting each char, you can check to see if you got EOF.
来源：https://stackoverflow.com/questions/4563617/how-to-terminate-a-program-with-ctrl-d