C# Tutorial P7 - Datatype conversions

[Admin]

Implicit conversion is done by the compiler:
1. When there is no loss of information if the conversion is done
2. If there is no possibility of throwing exceptions during the conversion

Example: Converting an int to a float will not loose any data and no exception will be thrown, hence an implicit conversion can be done.

Where as when converting a float to an int, we loose the fractional part and also a possibility of overflow exception. Hence, in this case an explicit conversion is required. For explicit conversion we can use cast operator or the convert class in c#.

Code samples:

Implicit Conversion Example
using System;
class Program
{
    public static void Main()
    {
        int i = 100;

        // float is bigger datatype than int. So, no loss of
        // data and exceptions. Hence implicit conversion
        float f = i;

        Console.WriteLine(f);
    }
}

Explicit Conversion Example
using System;
class Program
{
    public static void Main()
    {
        float f = 100.25F;

        // Cannot implicitly convert float to int.
        // Fractional part will be lost. Float is a
        // bigger datatype than int, so there is
        // also a possiblity of overflow exception
        // int i = f;

        // Use explicit conversion using cast () operator; don't have exception
        int i = (int)f;

        // OR use Convert class
        // int i = Convert.ToInt32(f); have exception

        Console.WriteLine(i);    // Output: 100
    }
}

Difference between Parse and TryParse
1. If the number is in a string format you have 2 options - Parse() and TryParse()
2. Parse() method throws an exception if it cannot parse the value, whereas TryParse() returns a bool indicating whether it succeeded or failed.
3. Use Parse() if you are sure the value will be valid, otherwise use TryParse()

using System;
class Program
{
    public static void Main()
    {
        string strNumber = "100";

        int i = int.Parse(strNumber);

        Console.Writeline(i);
    }
}

using System;
class Program
{
    public static void Main()
    {
        string strNumber = "100TG";

        int Result  = 0;

        bool IsConvertsionSuccessful = int.TryParse(strNumber, out Result);

        if (IsConvertsionSuccessful)
        {
            Console.Writeline(Result);
        }
        else
        {
            Console.WriteLine("Please enter a valid number");
        }
    }
}