Am I using array pointers in functions correctly here?

[JoeyS]

Hi, I'm relatively new to C++ and trying to write a program to aid in a physics project. I'm a little unsure of my understanding of how arrays are used in functions - I get that functions can't return an array but rather a pointer to it - so I wrote the following short program to see if I'm getting it right.

The program creates 3 small arrays, A, B and C. Function_1 fills arrays A and B based on an integer k=5, and function_2 performs a simple operation on arrays A and B and stores the results in array C. Main prints out the contents of all 3 arrays.

The program works fine and exactly the way I want it to but can someone please tell me if my use of arrays and pointers in the functions is correct? Or in other words, am I handling the arrays as efficiently as possible?

Thanks for any help.

#include <iostream>
using namespace std;


//Program involving 3 arrays.
//Function_1 fills the first two arrays.  Function_2 performs a simple
//operation on the first two arrays and then stores the result in the third 
//array. Main prints out the contents of all three arrays.



int main() {

int i;
int k=5;


int *array_A;
array_A = new int[5];

int *array_B;
array_B = new int[5];

int *array_C;
array_C = new int[5];

void* function_1(int k, int array_A[5], int array_B[5]);
void* function_2(int k, int array_A[5], int array_B[5], int array_C[5]);


function_1(k,array_A,array_B);			//call functions
function_2(k,array_A,array_B,array_C);


cout << endl << "array_A = ";			//print out arrays

for (i=0;i<=4;i++) {
	cout << array_A[i] << " ";
}

cout << endl << "array_B = ";

for (i=0;i<=4;i++) {
	cout << array_B[i] << " ";
}

cout << endl << "array_C = ";

for (i=0;i<=4;i++) {
	cout << array_C[i] << " ";
}



delete [] array_A;
delete [] array_B;
delete [] array_C;

return 0;
}



void* function_1(int k, int array_A[5], int array_B[5]) {

	for (int i=0;i<=4;i++) {
		array_A[i] = k+i;
	}

	for (int i=0;i<=4;i++) {
		array_B[i] = k*i;
	}

}


void* function_2(int k, int array_A[5], int array_B[5], int array_C[5]) {

	for (int i=0;i<=4;i++) {
		array_C[i] = k*(array_A[i] + array_B[i]);
	}

}

[Disch]

Looks fine except your functions are returning void* (a pointer) instead of void (nothing), which they should be.

I'm surprised your compiler isn't giving you errors because of that.

[JoeyS]

Thanks. My usual compiler does not give any errors and the program works fine but I just tried my other compiler which does give me errors, which removing the asterisk from void* corrects. I don't know why the first compiler does not produce any errors.