I need my C programs to pause and wait for key press after completion

[vertigoat]

I'm searched about this but haven't found anything conclusive. I recently started compiling from the command line and it creates an executable. I'm using a Mac by the way... Anyhow, one of the programs I wrote for school executes, asks for the two integers to be input, but then, it just disappears!

I need my terminal window to stay open so that I can at least see that my program works correctly!

Suggestions?

////  
//  Program Assignment 1 - Least Common Multiple
//  Desc: simple program to display LCM of two read integers
//


#include <stdio.h>


//func decs
int findLCM(int, int);
void getNums(int*, int*);


int main()
{
    int a;
    int b;
    
    getNums(&a, &b);
    printf("The Least Common Mutiple of %d and %d is:\t%d", a, b, findLCM(a, b));
    return 0;
}   //main


void getNums(int* a, int* b)
{
    printf("This program will accept (2) positive integers and calculate the Least Common Multiple");
    printf("\n\nEnter the first integer -> ");
    scanf("%d", a); //Why does this 'a' not need an address operator '&' preceding it?
    while (*a < 1) //Wanted to combine line 32 and line 33 but couldn't make it work. - Also, why does this 'a' need a '*' to work but the line 29 reference has nothing?
    {
        printf("\n\n*Integers MUST be positive.  Enter the first integer -> ");
        scanf("%d", a);
    }
    
    printf("\nEnter the second integer -> ");
    scanf("%d", b);
    while (*b < 1)
    {
        printf("\n\n*Integers MUST be positive.  Enter the second integer -> ");
        scanf("%d", b);
    }


        return;
}   //getNums




int findLCM(int a, int b)
{
    int i;
    for (i = 1; (i % a != 0) || (i % b != 0); i++)
    {
        
    }
    return i;
}   //findLCM

[raczzoli]

You can use getchar() at the end of your main function.

[vertigoat]

wow, that was a record! 3 minutes and an answer!

Alas, I just tried that and it doesn't work.

[oogabooga]

wow, that was a record! 3 minutes and an answer!
Alas, I just tried that and it doesn't work.

That's because your previous scanf's have left a newline in the buffer. You could try this:

char ch;  // at the top of main
scanf(" %c", &ch); // before the return 0 in main

Note that there's a space before the %c. That space will cause the newline (and any other extraneous whitespace) to be skipped.

[vertigoat]

If you don't mind, can you explain that? For whatever reason, I just don't comprehend what you are saying. I mean, I can cut and paste the code, but that won't help me understand what is happening.

[oogabooga]

I honestly don't know what to explain. You've used scanf in your code. It's one more use of that function, the documentation of which I assume you've read.

What exactly are you asking?

[vertigoat]

The last statement in that program is a printf. why can't I wait for a key press after that?

[oogabooga]

The last statement in that program is a printf. why can't I wait for a key press after that?

Who said you can't? That's exactly what I meant (read the comments).
I meant you to do this:

int main() {
    int a;
    int b;
    char ch;
    getNums(&a, &b);
    printf("The Least Common Mutiple of %d and %d is:\t%d", a, b, findLCM(a, b));
    scanf(" %c", &ch);
    return 0;
}