CODEWITHSUNDEEP
cwhile-loopinfinite-loop
MatthewS
MatthewS

Reputation: 485

Infinite while loop and control-c

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.)

Upvotes: 6

Views: 16617

Answers (2)

Gopi
Gopi

Reputation: 19874

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

Upvotes: 1

Rizier123
Rizier123

Reputation: 59701

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;

}

Upvotes: 16

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