Thread: while loop

Hi, I am trying to do a while loop that terminates the program when 99999 is entered but otherwise allows infinite integers to be entered. My problem is that when a negative number is entered it crashes and also when I enter a number it displays it twice. Any help would be much appreciated.

Code:

Code:

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


main()
{
int number;


   printf("Input an integer.\n");


   do {
      scanf("%d",&number);   /* read a single integer value in */
      printf("%d\n",number);
   } while (number != 99999);




}

Originally Posted by andyouf

Hi, I am trying to do a while loop that terminates the program when 99999 is entered but otherwise allows infinite integers to be entered. My problem is that when a negative number is entered it crashes and also when I enter a number it displays it twice. Any help would be much appreciated.

Code:

Code:

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


main()
{
int number;


   printf("Input an integer.\n");


   do {
      scanf("%d",&number);   /* read a single integer value in */
      printf("%d\n",number);
   } while (number != 99999);




}

It does not display a number twice what you see is an echo of what you entered and a display from the program making it seem like its displaying the number twice.

Aslaville is right, one is the echo from the terminal, the other is the print statement. As for crashing on negative numbers, I can't replicate your problem. Perhaps if you posted a sample run showing the input that causes the crash, we could help.

I see, thank you. Any idea on how to get it to display "Enter next integer" repeatedly in the output? Right now it just says that first line then only numbers.

Code:

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

main()
{
int number;



printf("Enter next integer:\n");

do {
scanf("%d",&number); /* read a single integer value in */

} while (number != 99999);


}

Originally Posted by andyouf

I see, thank you. Any idea on how to get it to display "Enter next integer" repeatedly in the output? Right now it just says that first line then only numbers.

Place your input prompt, "Enter next integer", inside the while loop.

-

Originally Posted by anduril462

Aslaville is right, one is the echo from the terminal, the other is the print statement. As for crashing on negative numbers, I can't replicate your problem. Perhaps if you posted a sample run showing the input that causes the crash, we could help.

i see the difference now, thank you. Yes it was not crashig on negatives i thing i may have put in a really long one need to change it to long long int

Originally Posted by megafiddle

Place your input prompt, "Enter next integer", inside the while loop.

-

Freaking brilliant! Thank you. I love when this stuff works, and as you can see I am very beginner. Onto getting a sum calc into that loop, which is beginning to get maddening. Any hints...I wouldn't mind. I get putting a sum calc in but putting one in that will accept any random set of numbers...

The normal approach to that is to declare a variable "sum" and initialize it to zero.
Then each time a new value is entered, add the new value to "sum", like this:

sum = sum + value;

This accumulates the values and keeps a running total of the values entered.

-

What I'm asking is is there a way to sum a random set of numbers where we do not know how many #'s will be input until the program is terminated with 99999 and then reads an output message on sum.

Originally Posted by megafiddle

The normal approach to that is to declare a variable "sum" and initialize it to zero.
Then each time a new value is entered, add the new value to "sum", like this:

sum = sum + value;

This accumulates the values and keeps a running total of the values entered.

-

Even when I just put "sum=0" under int main it crashes the prog...where do i declare sum?

Yes, just set up a variable "sum" and initialize it to zero.

Then each time a value is input, add that value to "sum":

Code:

scanf("%d",&number);
sum = sum + number;

This occors inside the loop, each time a new value is read in.

-

ugh....wont compile

Code:

/* Prompts user and gets integer numbers from keyboard, one number at a time. Ends program when 99999 entered. and displays various results.
        Written by: 
        Date:       10/20/14
*/
#include <stdio.h>
#include <stdlib.h>


int main()
{
int number;
sum=0;


    do {
      printf("Enter next integer:");
      scanf("%d", sum + &number);   /* read a single integer value input */


    } while (number != 99999);


}

Sorry, we are cross posting -

Declareing "sum" at the beginning of main should be fine.

What is your code now?

-

sum has no type:

sum = 0;

you need:

int sum = 0;

-