Thread: Absolute value of each element in a given array

I'm trying to get the absolute value of each element of an array, but am running into problems. I need to write a function that takes in as its arguments an array of numbers and the number of elements and outputs an array that contaions the absolute value of each number in the input array.

Code:

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

int abs(int *array, int N);

int main()
{
	int array[16] = {0,1,2,3,-4,5,6,7,-8,9,-10,11,12,13,14,20};
	int result;
	int absolute;
	
	absolute = abs(array,16);
	printf("abs is %i", absolute);

	return 0;
}

int abs(int *array, int N)
{
	int i;

	for(i=0; i<N, i++)
		if (array[i]<0)
			array[i]=array*(-1);

return array;

}

thanks for the help! we also need to print out the array to verify that it works correctly, I have this code but its not printing out right.

Code:

for ( i = 0; i < 16; i++ )
		absResult=absolute(array,16);
		printf("the absolute value is %d\n", absResult);

	return 0;

Originally Posted by DriftinSW20

Code:

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

int abs(int *array, int N);

int main()
{
	int array[16] = {0,1,2,3,-4,5,6,7,-8,9,-10,11,12,13,14,20};
	int result;
	int absolute;
	
	absolute = abs(array,16);
	printf("abs is %i", absolute);

	return 0;
}

int abs(int *array, int N)
{
	int i;

	for(i=0; i<N, i++)
		if (array[i]<0)
			array[i]=array*(-1);

return array;

}

There are a few errors.

The red disagree. In the prototype, you say abs() returns an int, but in the function, you return a pointer.

In green, you need to use an element of the array, not the pointer to the array.

In blue, even if you had the other things right, would only print one value. You might want to move the printf somewhere closer to your loop.

Todd

this is the corrected code that i have, its just not printing out right:

Code:

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

int absolute(int *array, int N);

int main()
{
	int array[16] = {0,1,2,3,-4,5,6,7,-8,9,-10,11,12,13,14,20};
	int ray[16];
	int i;

                for ( i = 0; i < 16; i++ )
		ray[i]=absolute(array,16);
		printf("the absolute value is %d\n", ray[i]);

	return 0;
}

int absolute(int *array, int N)
{
	int i;

	for(i=0; i<N; i++)
		if (array[i]<0)
			array[i] = array[i] * (-1);

}

Now you are calling your absolute() function 16 times, and each time it is called, it processes (the same) 16 integers.

Todd

then how would you make it so that it prints out each individual number from the resulting array?

You tell me! Do you want to print out the values in main() or in absolute()?

nevermind, i got it! thanks for the help!