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C# Basics
C# Basics
Basic Type Casting
Type Casting is the process of converting a value of one datatype to another. Type Casting is usually possible between numerically represented values. For-example we can convert a float
to an int
and an int
to a float
. However converting a string
to an int
does not make any logical sense and hence is not possible.
There are two types of typecasting, namely, Implicit Type Casting, and Explicit Type Casting.
Implicit Type Casting is when a value is automatically converted from one type to another, where needed.
main
int val1 = 10; long val2 = val1; // int is automatically converted to long float val3 = var1; // int is automatically converted to float double var4 = var1; // int is automatically converted to double
Whenever implicit type casting happens, it's always from a smaller to a bigger data type. The size of a data type is determined by how many bits of data it can store. For example int
can store 32 bits while long
can store 64 bits hence int
to long
implicit conversion is possible. Similarly float
to double
is possible as well.
The types ordered by their sizes are ordered from smallest to biggest below:
char
-> int
-> long
-> float
-> double
Explicit Type Casting is when the user specifically mentions the new data type of a value to which it should be converted. Explicit Type Casting is needed when we want to convert a value of a bigger data type to a smaller one, this is because there is almost always data loss when converting a value from a bigger to a smaller data type. For example, if we convert the float 3.14
to an integer, it will give 3
as a result hence we have lost some data during this conversion. Therefore the compiler needs an explicit command from the programmer to perform such a conversion.
main
using System; namespace ConsoleApp { internal class Program { static void Main(string[] args) { float val1 = 3.14f; int val2 = val1; // Error: Cannot implicitly convert type 'float' to 'int'. An explicit conversion exists (are you missing a cast?) Console.WriteLine(val1); Console.WriteLine(val2); } } }
To fix the error in the above code, we need to explicitly cast val1
to an integer value.
The syntax of a cast is (datatype) value
, for-example (int) 3.1415
. So in this case we will write (int) val1
:
main
using System; namespace ConsoleApp { internal class Program { static void Main(string[] args) { float val1 = 3.14f; int val2 = (int) val1; Console.WriteLine(val1); Console.WriteLine(val2); } } }
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