Thread: Error with my CodeBlocks compiler

Hello, I have been working on a problem in C (im teaching mysekf out of Kochans programming in C) and am running into a problem where my program does not print the output i desired.

When it first started i figured id done something wrong programming wise, only ti discover i simply needed to restart the IDE. It is now doing the same thing (worked before, nothing really changed, not working now)

Of course, there is always the chance i screwed up the code, though ive reviewed it a few times and cant find an issue.

Again, the issue is that the output either does not print, or does not show in the output. if the code below works for you, then its probably my ide and i need help solving it. Thank you!

Code:

#include <stdio.h>

void intToStr(int input)
{
    int x, negative = 0;

    char string[81];

        if (input < 0)
        {
        string[0] = '-';
        negative = 1;
        input=-input;
        }

    for (x = negative; string[x] != '\0'; x++)
    {
        string[x] = input%10;
            if (input < 1)
            {
            string[x] = input;
            string[x+1] = '\0';
            }
        input = input/10;
        printf ("%i", input);
    }
}

int main (void)
{
    int input;
    void intToStr(int input);

printf ("Please enter your number\n");
scanf ("%i", &input);

    intToStr(input);

    return 0;
}

I don't see anything wrong with your program. It's not printing anything because you're not telling it to print anything, the printf() in you function is probably never reached.

Jim

Originally Posted by jimblumberg

I don't see anything wrong with your program. It's not printing anything because you're not telling it to print anything, the printf() in you function is probably never reached.

Jim

I must be missing something then.

-If i input 2345 into the scanf command

-its inputted to the function.

-negative = 0 because the number is positive.

-string[x] = 5 (remainder of 2345 divided by ten)

-input divides by ten

-the printf command should show "234"

Thanks for looking at this.

I must be missing something then.

Yes you are.

The program probably isn't printing anything because that for loop is never being executed, you need to carefully check the for() condition section. When do you think that loop will ever execute?

What does the string string contain?

Jim

Originally Posted by jimblumberg

Yes you are.

The program probably isn't printing anything because that for loop is never being executed, you need to carefully check the for() condition section. When do you think that loop will ever execute?

What does the string string contain?

Jim

the condition is that string[x] != '\0'.

it should execute while there is no null character value in the string. when it hits that null character (which I add with the if statement below it) it should terminate the loop.

though string is uninitialized, so i suppose its possible that its producing an undefined value that equals the (null) character. It was functioning fine before though, but i know that often doesn't mean it was correct.

EDIT - the function is suppose to convert and integer to a string.

it should execute while there is no null character value in the string.

Yes and how do you know that the character in string[0] is not a '\0' prior to the start of the loop?

(which I add with the if statement below it) it should terminate the loop.

If the loop is never entered what is inside the body of the loop makes no difference.

though string is uninitialized, so i suppose its possible that its producing an undefined value that equals the (null) character.

Using an uninitialized value produces undefined behavior, so anything can happen. If string[0] happens to be '\0' the loop will not execute, which is what I'm seeing with my compiler.

You need to always initialize all variables before you try to use them in a "calculation" or "comparison".


Jim

Ah thank you both. both answers helpful in different ways