# Use a for statement

Difference of Squares in C#
``````public static class DifferenceOfSquares
{
public static int CalculateSquareOfSum(int max)
{
var sum = 0;

for (var i = 1; i <= max; i++)
sum += i;

return sum * sum;
}

public static int CalculateSumOfSquares(int max)
{
var sumOfSquares = 0;

for (var i = 1; i <= max; i++)
sumOfSquares += i * i;

return sumOfSquares;
}

public static int CalculateDifferenceOfSquares(int max) =>
CalculateSquareOfSum(max) - CalculateSumOfSquares(max);
}
``````

### Method: `CalculateSquareOfSum()`

The square of the sum is defined as: sum all numbers from `1` to the provided `max`, and then square that number.

Let's start by defining a variable to hold the sum:

``````var sum = 0;
``````

We can then iterate over the number using a `for` statement and add each number to the sum:

``````for (var i = 1; i <= max; i++)
sum += i;
``````

The last step is to run the square of the sum:

``````return sum * sum;
``````

### Method: `CalculateSumOfSquares()`

The calculate the sum of the squares, we once again start out with creating an enumerable of the numbers from `1` to `max`:

Let's start by defining a variable to hold the sum:

``````var sumOfSquares = 0;
``````

We can then iterate over the number using a `for` statement and add each number's square to the sum:

``````for (var i = 1; i <= max; i++)
sumOfSquares += i * i;
``````

The last step is to run the sum of the squares:

``````return sumOfSquares;
``````

### Method: `CalculateDifferenceOfSquares()`

The `CalculateDifferenceOfSquares()` method is nothing more than calling the two methods we just created:

``````public static int CalculateDifferenceOfSquares(int max) =>
CalculateSquareOfSum(max) - CalculateSumOfSquares(max);
``````
29th May 2024 · Found it useful?