The unsafe code or the unmanaged code is a code block that uses a pointer variable. A pointer is a variable whose value is the address of another variable i.e., the direct address of the memory location. Similar to any variable or constant, you must declare a pointer before you can use it to store any variable address.

If you are using Visual Studio IDE then you need to enable use of unsafe code in the project properties.

To do this:

·    Open project properties by double clicking the properties node in the Solution Explorer.

·    Click on the Build tab.

·    Select the option "Allow unsafe code".

For example,

using System;
namespace UnsafeCodeEx
{
    class TestPointer
    {
        public unsafe static void Main()
        {
            TestPointer p = new TestPointer();
            int var1 = 10;
            int var2 = 20;
            int* x = &var1;
            int* y = &var2;
            p.DemoMultiplication(x, y);
            Console.ReadKey();
        }
        public unsafe void DemoMultiplication(int* p, int* q)
        {
            int result = *p + *q;
             Console.WriteLine("Multiplication is: " + result);
        }
    }
}

Output:

Similar way, you can write more program related to unsafe code .