C - How to use a string with scanf multiple times

Question

Here's my code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void)
{
     char terminal[100];

     printf("Enter cmds: ");
     scanf(" %s", terminal);

     if(strcmp(terminal, "help") == 0){
           printf("test");
           scanf(" %s", terminal); // trying to detect if a user types
                                   // "help" the menu will pop up again
     }

     return 0;
     }

When a user types "help", the menu pops up, (good so far). But when they type "help" again, the menu does not pop up. Does anybody know what is going on?

where did you code for the again part?

Sourav Ghosh
– Sourav Ghosh

2017-01-29 14:56:09 +00:00
Commented Jan 29, 2017 at 14:56 — Sourav Ghosh
– Sourav Ghosh, Commented Jan 29, 2017 at 14:56
Perhaps a do...while loop is what you want?

Spikatrix
– Spikatrix

2017-01-29 14:56:28 +00:00
Commented Jan 29, 2017 at 14:56 — Spikatrix
– Spikatrix, Commented Jan 29, 2017 at 14:56
How is VB.NET related to this??

Visual Vincent
– Visual Vincent

2017-01-29 14:57:11 +00:00
Commented Jan 29, 2017 at 14:57 — Visual Vincent
– Visual Vincent, Commented Jan 29, 2017 at 14:57

pateryan · Accepted Answer · 2017-01-29 17:23:41Z

2

The initial comments hit the nail on the head here. You need to loop over new input multiple times. This can be done fairly easily.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void)
{
    char terminal[100];

    printf("Enter cmds: ");

    // this expression will return zero on invalid input, exiting the loop
    while (scanf("%99s", terminal) == 1) {  
        // your if statement and other code you want to repeat go here.
    }
}

To better encapsulate this kind of behaviour, defining some sort of function that compares strings and returns an element of an enum is a very common practice, but not required in this question.

edited Jan 29, 2017 at 17:23

answered Jan 29, 2017 at 15:27

pateryan

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