Thread: Math program

I don't understand why my program doesn't work... Its supposed to find the sum of:

1*2 + 3*4 + 5*6 ... + 2003*2004
When i output what is being held in array[0] it gives me like 4.022+06 or something whereas it should be 1 and array[1] should be two

Code:

#include <iostream.h>
#include <math.h>

void main() {
	int i, j;
	double array[1002];
	double sum=0;
	double square;

	for (j=0; j<1002; j++) {
		for (i=1; i<=2004; i+=2) {
			array[j]=i*(i+1);
		}
	}

	for (i=0; i<1002; i++) {
		sum+=array[i];
	}
	cout<<array[0]<<endl;
        cout<<sum<<endl;
}

Oh yeah you're right thanks a lot

k i fixed it

Code:

	for (j=1; j<=1002; j++) {
		array[j-1]=(2*j)*(2*j -1);
	}

Code:

for (j=0; j<1002; j++) {
		for (i=1; i<=2004; i+=2) {
			array[j]+=i*(i+1);
		}
	}

would this work note you must init the array to zero

It would work but why have an array with 1002 elements, that are all the same?

Code:

int sum(int maxNumber)
{
   if (maxNumber<=2) return maxNumber;
   return maxNumber*(maxNumber-1)+sum(maxNumber-2);
}

Thought I'd try a recursive solution.
Is this correct. Not very pretty thats for sure.

well my new and improved code sets

array [0]: 1*2
array [1]: 3*4
array [2]: 5*6

...

array [1002] 2003*2004