Enter key in basic c program

#1 26-Mar-2005, 12:11

Sorry if this question has been asked before but I couldnt find anything on it using google or the GID search.

Quick question that can probably be answered easily.

I have a program that I'm doing for school and the only problem I'm having is with the Enter key.
What I want to do is: using a loop, calculate the average number of a certain amount of numbers given by the user.
All that is fine and working, but I'm also supposed to handle the situation if the user doesnt enter any numbers and just presses Enter. The program should then display "No input, quitting..." and then quit.

I cant figure out what C recognizes as the enter key. Basicly I want something like this

if (x == Enter Key)
{
printf ("No input, quitting");
delay (2000); exit (EXIT_SUCCESS);
}

Any help will be greatly appreciated.

Dr. Evil · #2 26-Mar-2005, 13:20

Newline = 10 = 0xA.

davekw7x · #3 26-Mar-2005, 16:09

Quote:

Originally Posted by hopesfall

Sorry if this question has been asked before but I couldnt find anything on it using google or the GID search.

Quick question that can probably be answered easily.

I have a program that I'm doing for school and the only problem I'm having is with the Enter key.
What I want to do is: using a loop, calculate the average number of a certain amount of numbers given by the user.
All that is fine and working, but I'm also supposed to handle the situation if the user doesnt enter any numbers and just presses Enter. The program should then display "No input, quitting..." and then quit.

I cant figure out what C recognizes as the enter key. Basicly I want something like this

if (x == Enter Key)
{
printf ("No input, quitting");
delay (2000); exit (EXIT_SUCCESS);
}

Any help will be greatly appreciated.

I would probably use fgets() in a loop to read the entire line. If the only thing is a newline, then you know to quit. Otherwise, you get whatever information you expect to see on the line (combinations of strtok(), scanf(), strtol() or whatever you want.)

CPP / C++ / C Code:

#include <stdio.h>

int main()
{

  int x;
  int count = 0;

  char buffer[BUFSIZ];

  printf("Enter a decimal integer: ");
  while (fgets(buffer, BUFSIZ, stdin)) {/* exit upon EOF */
    if (buffer[0] == '\n') {
      break;
    }
    if (sscanf(buffer, "%d", &x) != 1) { /* guard against non-decimal digit chars */
      printf("Invalid decimal number; try again.\n");
      continue;
    }
    /* do something useful with x here; I just print it out */
    printf("            You entered  %d\n\n", x);
    count++;
    printf("Enter a decimal integer: ");
  }

  printf("Total number of valid entries = %d\n", count);
  return 0;
}

Regards,

Dave

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