Int.MaxValue

In C# an int has a maximum value it can represent. This value is found with int.MaxValue. The minimum value too can be determined with int.MinValue.

Numeric types, like int, uint, short and ushort, have specific max values. These are constants—they never change. But we do not need to memorize them to use them.

MaxValue and MinValue are constant values. They can be accessed anywhere with their composite names. These consts make programs easier to understand.

short.MaxValue:  32767
short.MinValue: -32768
ushort.MaxValue: 65535
ushort.MinValue: 0
int.MaxValue:    2,147,483,647
int.MinValue:   -2,147,483,648
uint.MaxValue:   4,294,967,295
uint.MinValue:   0
long.MaxValue:   9,223,372,036,854,775,807
long.MinValue:  -9,223,372,036,854,775,808

First example

Often we must keep track of the lowest number found. We can use int.MaxValue to start the value high, and then any lower number will be valid.

using System;

int[] integerArray = new int[]
{
    10000,
    600,
    1,
    5,
    7,
    3,
    1492
};

// This will track the lowest number found
int lowestFound = int.MaxValue;

foreach (int i in integerArray)
{
    // By using int.MaxValue as the initial value, this check will usually succeed.
    if (lowestFound > i)
    {
        lowestFound = i;
        Console.WriteLine(lowestFound);
    }
}
10000
600
1

Min, max

We can access MinValue and MaxValue in the same way. Be careful not to assign an unsigned value to int.MinValue—it is a negative number.

using System;

// Display min and max.
Console.WriteLine("MIN: " + int.MinValue);
Console.WriteLine("MAX: " + int.MaxValue);
MIN: -2147483648
MAX: 2147483647

Discussion

In C# and Windows, there is no performance boost in using smaller data types in loops. Using ushort instead of int just creates unclear code.

Constants

When you have other constants to define, declare them as "public const int ValueName". This has great performance, and is standard and clear. It works well with IntelliSense.

The max and min constants on number types (like int) are often useful in C# programs. We should avoid typing out numbers like -2,147,483,648 unless needed.