I am trying to create a c program that will continuously take inputs from stdin till exit is entered

Question

Here is the code I wrote:

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define SIZE 50

int main(int argc, char *argv[])
{
  char str[SIZE];
  char str2[] = "exit";
  //fgets(str, sizeof str, stdin);
  while (strcmp(str, str2) != 0)
  {
    fgets(str, sizeof str, stdin);
    printf("%s", str);
  }
  return 0;
}

But it doesn't seem to exit and is stuck in an infinite loop.

The string returned by `fgets` will include the newline (`\n`) character. Try using `strncmp(str, str2, 4) != 0`. — Adrian Mole, Feb 13 '20 at 22:26
`str` is uninitialised the first time through; maybe use a different looping mechanism? — Neil, Feb 13 '20 at 22:27
Maybe this will help: [Removing trailing newline character from fgets() input](https://stackoverflow.com/q/2693776/10871073). — Adrian Mole, Feb 13 '20 at 22:30
Does this answer your question? [Removing trailing newline character from fgets() input](https://stackoverflow.com/questions/2693776/removing-trailing-newline-character-from-fgets-input) — clearlight, Feb 14 '20 at 03:30

anastaciu · Accepted Answer · 2020-02-13T22:43:38.737

4

One solution would be to use:

char str2[]="exit\n";

But a do - while cycle would be best:

int main () {    
    char str[SIZE];
    char str2[]="exit\n";
    do {
        fgets(str, sizeof(str), stdin);
        printf("%s",str);
    } while(strcmp(str,str2));
    return 0; 
}

Since in the first iteration of you cycle str is empty.

edited Feb 13 '20 at 22:43

answered Feb 13 '20 at 22:29

anastaciu

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This is probably the most lazy ways imaginable, (and one of the fastest.) I approve. – Neil Feb 13 '20 at 22:38
@rohithp, glad to help, extended credits to [Adrian Mole](https://stackoverflow.com/users/10871073/adrian-mole) and [Neil](https://stackoverflow.com/users/2472827/neil) – anastaciu Feb 13 '20 at 22:39

I am trying to create a c program that will continuously take inputs from stdin till exit is entered

1 Answers1