I believe there is a logical math problem with my code, but I cannot put my finger where is it and why

This my code and when i try to test the difference for input of 100 i get 24501794 instead of 25164150, here is my code:

class DifferenceOfSquaresCalculator {

    

    int computeSquareOfSumTo(int input) {
        int sumOfNatural = 0;
        int sumOfNaturalSquared = 0;
        for (int i = 1; i < input; i++){
            sumOfNatural+=i;
        }
        sumOfNaturalSquared = (int) Math.pow(sumOfNatural,2);
        return sumOfNaturalSquared;
    }

    int computeSumOfSquaresTo(int input) {
        int sumOfSquaredNaturals = 0;
        for (int i = 1; i < input; i++){
            i = (int) Math.pow(i, 2);
            sumOfSquaredNaturals+=i;
        }
        return sumOfSquaredNaturals;
    }

    int computeDifferenceOfSquares(int input) {
        int difference = computeSquareOfSumTo(input) - computeSumOfSquaresTo(input);

        return difference;
    }

}

>Solution :

You have two problems with this code.

At first, you count the series excluding the last number:

for (int i = 1; i < input; i++)
should be
for (int i = 1; i <= input; i++)

At second, in your computeSumOfSquaresTo you are changing the loop variable i inside the loop.
Try this instead:

int computeSumOfSquaresTo(int input) {
    int sumOfSquaredNaturals = 0;            
    for (int i = 1; i <= input; i++) {       
        sumOfSquaredNaturals += i * i;       
    }                                        
    return sumOfSquaredNaturals;             
}