Thread: Not sure why this doesn't work...

Basically I'm trying to make this program so if you change the value of cupOfMarbles it will count up and print 5...6...7...8...9...10 and then stop (in this example) or if it is over 10 it will count down until the loop reaches 10. Nothing happens though, no errors on the compile either so my logic must be off or values aren't being passed. Any suggestions on what I need to do to fix this (without getting too complicated) I'm still learning

Thanks

Code:

#include <stdio.h>

void UnderTen( void );   // cupOfMarbles is under 10
void OverTen( void );    // cupOfMarbles is over 10

int cupOfMarbles;

int main (int argc, const char * argv[]) {

	cupOfMarbles = 5;	 // change this value to get different results
	
	if ( cupOfMarbles == 10 )
		printf( "You already have 10 marbles in this cup!\n" );
	
	if ( cupOfMarbles < 10 )
		UnderTen();
		
	if ( cupOfMarbles > 10 )
		OverTen();

    return 0;
}


void UnderTen( void ) {
	int i;
for ( i = cupOfMarbles ; i == 10; i++ )
	printf( " There are currently %d marbles in the cup!\n", i );
}


void OverTen( void ) {
	int i;
for ( i = cupOfMarbles ; i == 10; i-- )
	printf( "There are currently %d marbles in the cup!\n", i );
}

Originally Posted by lucidrave

values aren't being passed

Code:

#include <stdio.h>
	if ( cupOfMarbles < 10 )
		UnderTen(COMPLETE LACK OF VALUE HERE);
		
	if ( cupOfMarbles > 10 )
		OverTen(COMPLETE LACK OF VALUE HERE);

No kidding.

there is no value in there because i'm just calling a function... if its under 10 then i call the function UnderTen();

Originally Posted by lucidrave

there is no value in there because i'm just calling a function... if its under 10 then i call the function UnderTen();

And has that worked for you for any other functions? Do you just call printf() and not put anything in the parentheses?

I even simplified the code as much as I could (no function calls) and it only works if the value is 10... anything lower or higher doesn't work. Is my logic flawed here? Please help

Code:

#include <stdio.h>

int main (int argc, const char * argv[]) {

	int cupOfMarbles;

	cupOfMarbles = 9;	 // change this value to get different results
	
	if ( cupOfMarbles == 10 ) {
		printf( "You already have 10 marbles in this cup!\n" );
	}
	
	
	if ( cupOfMarbles < 10 ) {	
		for ( cupOfMarbles ; cupOfMarbles == 10; cupOfMarbles++ )
			printf( "There are currently %d marbles in the cup!\n", cupOfMarbles );
	}
		
	
	if ( cupOfMarbles > 10 ) {
		for ( cupOfMarbles ; cupOfMarbles == 10; cupOfMarbles-- )
			printf( "There are currently %d marbles in the cup!\n", cupOfMarbles );
	}

    return 0;
}

For loops only work while the middle statement is true.

And has that worked for you for any other functions? Do you just call printf() and not put anything in the parentheses?

What are you talking about? There are functions that don't take parameters... his don't.

lucidrave: the reason your original program doesn't work the way you expect is that your for loops are wrong. UnderTen() gets called if cupOfMarbles is under 10, but the loop is set to go if cupOfMarbles is equal to 10. That wont work. Your for loop in UnderTen() should be:

Code:

for ( i = cupOfMarbles ; i <= 10; i++ )

I'll let you figure out the OverTen() function.

Originally Posted by bithub

What are you talking about? There are functions that don't take parameters... his don't.

It hadn't occurred to me that he would use a global variable to avoid passing a parameter to a function.

It hadn't occurred to me that he would use a global variable to avoid passing a parameter to a function.

From the difficultly level of his problem, I'd say it's quite possible he hasn't even learned about passing parameters yet.

Yeah! It works now! Thanks for the info guys, bithub's your tip got it working. But tabstop reminded me that for only works when a statement is true.

Code:

There are currently 5 marbles in the cup!
There are currently 6 marbles in the cup!
There are currently 7 marbles in the cup!
There are currently 8 marbles in the cup!
There are currently 9 marbles in the cup!
There are currently 10 marbles in the cup!

yeah, the next chapter in the book i'm reading talks about pointers and parameters... i haven't quite got there yet. i'm trying to master the different types of loops and understand when it is best to use them before i move on.

thanks again.

any extra advice is always helpful