Thread: Using both a Recursive and Iterative Functions

This code needs to have both a recursive and iterative function, with the iterative function having the loop. How does this need to be done?

Code:

//Program Purpose: computes the greatest common divisor (gcd) of two numbers given that 
//				   gcd is the product of the integers’ common factors.

#include <stdio.h>
#include <math.h>
int main (void)
{
	/*Define Variables*/
	int x;
	int y;
    int remainder;
	int gcm;

	
	/*Get user Input*/
	printf("Input first number-> ");
	scanf("%d", &x);
	printf("Input second number-> ");
	scanf("%d", &y);

	/* Compute */
	x=abs(x);
	y=abs(y);
	

	do{
		remainder=x%y;
		x=y;
		y=remainder;
	}
	while(remainder!=0);
	
	gcm=x;
	printf("gcm = %d \n", gcm);
	
	return 0;
}

well the specifications of the way my professor wants this program to be written is with two functions, one a recursive and the other an iterative function with a loop. From what I heard from her, both have to be used for me to get any credit and im not sure how to do this.

So you seem to have the loop/iterative part done, except for the "putting it in a function" part. Now rewrite the calculation using recursion -- instead of loop back to the top, it's call the function with smaller numbers.

so like this?

Code:

#include <stdio.h>
#include <math.h>

void iterative(int x, int y);
int recursive (int x, int y);

int main (void)
{
	/*Define Variables*/
	int x;
	int y;
	
	/*Get user Input*/
	printf("Input first number-> ");
	scanf("&#37;d", &x);
	printf("Input second number-> ");
	scanf("%d", &y);

	/* Compute */
	x=abs(x);
	y=abs(y);
	
	iterative(x,y);
	
	/*End Program*/
	return 0;
}
/*-----------------------------------------------------------*/
void iterative(int x, int y)
{
int remainder;
int gcm;

	do{
		remainder=recursive(x, y);
		x=y;
		y=remainder;
	}
	while(remainder!=0);
	
	gcm=x;
	printf("gcm = %d \n", gcm);
	return(0);
	}

/*----------------------------------------------------------*/
int recursive(int x, int y)
{
	return(x%y);
}

i mean it still gives me the right output, but i dont think im calling the recursive again am I?

so what needs to be in the recursive part, do you think?

I think i figured it out or at least i am getting the right results with my test, but does this make sense to you guys?

Code:

#include <stdio.h>
#include <math.h>

void iterative(int x, int y);
int recursive (int x, int y, int remainder);

int main (void)
{
	/*Define Variables*/
	int x;
	int y;
	int remainder=1;
	
	/*Get user Input*/
	printf("Input first number-> ");
	scanf("%d", &x);
	printf("Input second number-> ");
	scanf("%d", &y);

	/* Compute */
	x=abs(x);
	y=abs(y);
	
	printf("Recursive GCM = %d \n", recursive(x, y, remainder));
	iterative(x,y);
	/*End Program*/
	return 0;
}
/*-----------------------------------------------------------*/
void iterative(int x, int y)
{
int remainder;
int gcm;

	do{
		remainder=x%y;
		x=y;
		y=remainder;
	}
	while(remainder!=0);
	
	gcm=x;
	printf("Iterative GCM = %d \n", gcm);
	return(0);
	}

/*----------------------------------------------------------*/
int recursive(int x, int y, int remainder)
{
	if(remainder==0)
		return x;
	else
	{
		remainder=x%y;
		x=y;
		y=remainder;
		return recursive(x, y, remainder);
	}
}
/*--------------------------------------------------------*/

i can just print both of the functions results to the screen and i think that may work for my professor