C ා basis: definition, out, ref, params of function (method)

;

C ා is purely object-oriented, which is different from C + +. For example, the method declaration format of C ා is as follows:

[public] static return value type method name (parameter list)
{
Method body
}


public access modifier, which can be omitted

There are more modifiers than C + +, and they have to be decorated with static. Static functions can only access static members. Others are basically the same as C + +.

C ා has reference values similar to C + +, which can be realized by out and ref

(1) Use of out modifier parameters

using System;

namespace out keyword
{
    class Program
    {
        //Adding an out keyword before a function parameter indicates that the parameter will also be returned, which is similar to the C + + reference value passing. A parameter can have multiple out parameters
        static int testOut(int num, out string str)
        {
            str = "success";
            return num;
        }

        static void Main(string[] args)
        {
            string str;

            //When parameters are passed to formal parameters, out must also be added
            int ret = testOut(12, out str);

            Console.WriteLine("ret = {0}, str = {1}", ret, str);
            Console.ReadKey();
        }
    }
}

(2) The usage of ref modifying parameter

using System;

namespace ref keyword
{
    class Program
    {
        static void setMoney(ref int money)
        {
            money += 1000;
        }

        static void Main(string[] args)
        {
            int salary = 2000;

            //When using ref, the parameter must be assigned outside the method, and the argument must be decorated with ref
            setMoney(ref salary);
            Console.WriteLine("salary = " + salary);
            Console.ReadKey();
        }
    }
}

(3) params

using System;

namespace params Use of keywords
{
    class Program
    {
        static void Main(string[] args)
        {
            int max = getMax(12, 45, 11, 89, 6);

            Console.WriteLine("The largest number is: " + max);
            Console.ReadKey();
        }

        //params means that parameters can be passed into any number of int types to form an array
        //When params is used, the parameter list of a function has only one parameter. When there are multiple parameters, it can only be used as the last parameter
        static int getMax(params int[] array)
        {
            int max = 0;
            foreach(var it in array)
            {
                if (max <= it)
                    max = it;
            }

            return max;
        }
    }
}

Posted by micah1701 on Sun, 03 May 2020 05:16:25 -0700