# Numbers

We can create integers like so:

var number = 43;

But what about floating-point numbers or decimals?

Well, we can just add a specific letter after the number:

var floatNumber = 12F;  // float
var doubleNumber = 23D; // double
var decimalNumber = 5M; // decimal
var longNumber = 12L;   // long

So, we need:

• F for float
• D for double
• M for decimal
• L for long

Also, we can create double numbers like so:

var doubleNumber = 12.34;

For integers, we can can unsigned numbers when we don't care about negative numbers and we want only positive ones:

var unsignedNumber = 12U;
Console.WriteLine(unsignedNumber);

So, it means that the max value for unsigned should be double the max one for all ints, doesn't it? 😏

var maxInt = int.MaxValue;
var maxIntUnsigned = UInt32.MaxValue;

Console.WriteLine(maxIntUnsigned > maxInt * 2); // True

# isNaN

To check if a value if not a number, you need to use double.isNaN:

var number = double.NaN;
var result = double.IsNaN(number);
Console.WriteLine(result); // True

Also, whenever you try to divide a number by 0, then the DivideByZeroException is thrown.

# Overflowing

We can get the maximum value of an integer like this:

var maxValue = int.MaxValue;
Console.WriteLine(maxValue); // 2147483647

If we increment this value, then the maxValue get the minumum value: 😱

maxValue++;
Console.WriteLine(maxValue); // -2147483648

And this can be a real problem because this behavior passes as normal. This is called integral overflow.

If you want to throw exceptions when this happens, you can use checked:

checked
{
    maxValue++;
    Console.WriteLine(maxValue);
}

This time, it throws the OverflowException exception because the incrementing operation caused an overflow.

We can also check only an statement:

checked(maxValue++);

So make sure that you are aware of this issue and when this might happen, you should use checked.