C#提供out关键字将参数作为输出类型传递。它类似于引用类型,不同之处在于它在传递之前不需要初始化变量。无涯教程必须使用out关键字将参数作为输出类型传递。当无涯教程希望一个函数返回多个值时,它很有用。
using System; namespace OutParameter { class Program { // 用户定义的函数 public void Show(out int val) // 输出参数 { int square = 5; val = square; val *= val; // Manipulating value } static void Main(string[] args) { int val = 50; Program program = new Program(); // 创建对象 Console.WriteLine("Value before passing out variable " + val); program.Show(out val); // 将输出参数传入函数 Console.WriteLine("Value after recieving the out variable " + val); } } }
输出:
Value before passing out variable 50 Value after receiving the out variable 25
下面的示例演示了函数如何返回多个值。
using System; namespace OutParameter { class Program { // 用户定义的函数 public void Show(out int a, out int b) // 输出函数 { int square = 5; a = square; b = square; // Manipulating value a *= a; b *= b; } static void Main(string[] args) { int val1 = 50, val2 = 100; Program program = new Program(); //创建对象 Console.WriteLine("Value before passing \n val1 = " + val1+" \n val2 = "+val2); program.Show(out val1, out val2); // 传递输出函数 Console.WriteLine("Value after passing \n val1 = " + val1 + " \n val2 = " + val2); } } }
输出:
Value before passing val1 = 50 val2 = 100 Value after passing val1 = 25 val2 = 25
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