How do I solve a Balanced array problem

[CollinsLainzo]

Hello guys,

So I have this problem: "An array is called balanced if its even numbered elements (a[0], a[2], etc.) are even and its odd numbered elements (a[1], a[3], etc.) are odd. Write a function named isBalanced that accepts an array of integers and returns 1 if the array is balanced, otherwise it returns 0. Examples: {2, 3, 6, 7} is balanced since a[0] and a[2] are even, a[1] and a[3] are odd. {6, 7, 2, 3, 12} is balanced since a[0], a[2] and a[4] are even, a[1] and a[3] are odd. {7, 15, 2, 3} is not balanced since a[0] is odd. {16, 6, 2, 3} is not balanced since a[1] is even. The function signature should be int isBalanced(int[ ] a).

and I have this solution:

#include <iostream>
using namespace std;
int isBalanced(int a[], int len);
int main()
{
	int isBal=1;
	int balArr[50];
	int size, i;
	cout<<"Enter array size: "<<endl;
	cin>>size;
	cout<<"Enter Array Elements: "<<endl;
	for(int i=0; i<size; i++)
	{
		cin>>balArr[i];
	}
	cout<<isBalanced(balArr,size);
}

int isBalanced(int a[], int len)
{
	int isBalanced =1;
	
	for(int i=0; i<a[len]; i+=2)
	{
		if((a[i]%2!=0)||(i%2!=0))
		{
			isBalanced=0;
		}
	}
	for(int j=1; j<a[len]; j+=2)
	{
		if((a[j]%2==0)||(j%2==0))
		{
			isBalanced=0;
		}
	}
	return isBalanced;
}

Problem is, it only works for the first example and not for all. I need some support.

[lastchance]

On lines 23 and 30 it should be just len, not a[len].

You don't need the checks i%2!=0 because i is even anyway. (You are going up from 0 in steps of 2.)
Similarly, you don't need the check j%2==0.

isBal declared on line 6 is unused.

Variable i declared on line 8 is also unused. (Another variable - also named i! - comes into scope on line 12.)

You would also be entitled to return 0 as soon as you found an imbalance, not continue checking the rest.

[CollinsLainzo]

Fantastic!!! It works perfectly. @lastchance Thanks a lot, you even optimized my code like some kind of compiler picking up on all the unused variables and stuff. Hope you won't mind I chat you in private when I have issues as I am just a bit above beginner level and I am preparing for some online test. I kind of have a whole lot of practice exercises to solve on functions and arrays like the one above. Thanks again.

[lastchance]

CollinsLainzo wrote:

you even optimized my code like some kind of compiler picking up on all the unused variables

Err, have to confess, ... I just used cpp.shell, the forum compiler (click the gear wheel to the top-right of the code sample). It picked up the majority of issues.

Best to put all correspondence in the open forum. You will get more and probably better replies.