Infinite while loop and control-c

Question

So, I wrote the following code:

void main(void) {

int charNums[ALPHABET], i = 1;
char word[MAX];

while(i) {

    initialize(charNums, word);

    getString(word);
    setLetters(charNums, word);

    getString(word);
    checkLetters(charNums, word);

    if(isZero(charNums))
        printf("Anagram\n");
    else
        printf("Not anagram\n");
}
}

The while loop is infinite, which it is supposed to be. My professor said something about using CTRL-C to exit the infinite while loop, but that doesn't work with what I've coded. Am I missing something simple or what? Can someone please point me in the right direction? Thank you! (Note: this is only a portion of the code.)

You can test a condition with `if` and the use `break;` to break the loop — Rizier123, Nov 17 '14 at 04:27
Can you make the condition hitting ctrl-c? If so, then how does one go about coding something like that? — MatthewS, Nov 17 '14 at 04:29
Made a answer with a signal handler so it checks if your hitting ctrl-c! — Rizier123, Nov 17 '14 at 04:51
Appreciate all the help. Apparently, according to the professor, he made a mistake and, ctrl-c to exit a program in Visual Studio, it does not work with the development environment we are using. Thanks again! — MatthewS, Nov 18 '14 at 01:04

score 15 · Accepted Answer · answered Nov 17 '14 at 04:39

This should work for you:

(Here i'm adding a signal handler which checks if you press ctrl + c and if so it's stops the loop)

#include <unistd.h>
#include <stdio.h>
#include <signal.h>

volatile sig_atomic_t stop;

void inthand(int signum) {
    stop = 1;
}

int main(int argc, char **argv) {

    signal(SIGINT, inthand);

    while (!stop)
        printf("loop\n");

    printf("exiting safely\n");
    system("pause");

    return 0;
}

So i think your program should look something like this:

#include <unistd.h>
#include <stdio.h>
#include <signal.h>

volatile sig_atomic_t stop;

void inthand(int signum) {
    stop = 1;
}

int main(int argc, char **argv) {

    signal(SIGINT, inthand);

    int charNums[ALPHABET], i = 1;
    char word[MAX];

    while(!stop) {

        initialize(charNums, word);

        getString(word);
        setLetters(charNums, word);

        getString(word);
        checkLetters(charNums, word);

        if(isZero(charNums))
            printf("Anagram\n");
        else
            printf("Not anagram\n");
    }

    printf("exiting safely\n");
    system("pause");
    return 0;

}

dont forget to initialize stop =0 before the while loop – andrvibo Mar 15 '18 at 20:35 — andrvibo, Mar 15 '18 at 20:35

Gopi · Answer 2 · 2014-11-17T06:24:28.863

1

while(1)
{
}

This is a infinite loop there should be some condition in the while loop to break out of it. ctrl+c will terminate you program. So instead of ctrl+c there should be some condition within the loop to break out of it. If ctrl+c should be used to break out of the loop then you need to use a signal handler to handle your ctrl+c signal

edited Nov 17 '14 at 06:24

answered Nov 17 '14 at 04:28

Gopi

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We were specifically told to use ctrl-c – MatthewS Nov 17 '14 at 04:29
@user3727648 Then you need to use signal handler to handle `ctrl+C` – Gopi Nov 17 '14 at 04:39

Infinite while loop and control-c

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