C# 语言规范--语句

语句 示例
语句列表和块语句 
static void Main() {
            F();
            G();
            {
            H();
            I();
            }
            }
标记语句和 goto 语句 
static void Main(string[] args) {
            if (args.Length == 0)
            goto done;
            Console.WriteLine(args.Length);
            done:
            Console.WriteLine("Done");
            }
局部常数声明 
static void Main() {
            const float pi = 3.14f;
            const int r = 123;
            Console.WriteLine(pi * r * r);
            }
局部变量声明 
static void Main() {
            int a;
            int b = 2, c = 3;
            a = 1;
            Console.WriteLine(a + b + c);
            }
表达式语句 
static int F(int a, int b) {
            return a + b;
            }
            
static void Main() {
            F(1, 2);  // Expression statement
            }
if 语句 
static void Main(string[] args) {
            if (args.Length == 0)
            Console.WriteLine("No args");
            else
            Console.WriteLine("Args");
            }
switch 语句 
static void Main(string[] args) {
            switch (args.Length) {
            case 0:
            Console.WriteLine("No args");
            break;
            case 1:
            Console.WriteLine("One arg ");
            break;
            default:
            int n = args.Length;
            Console.WriteLine("{0} args", n);
            break;
            }
            }
while 语句 
static void Main(string[] args) {
            int i = 0;
            while (i < args.Length) {
            Console.WriteLine(args[i]);
            i++;
            }
            }
do 语句 
static void Main() {
            string s;
            do { s = Console.ReadLine(); }
            while (s != "Exit");
            }
for 语句 
static void Main(string[] args) {
            for (int i = 0; i < args.Length; i++)
            Console.WriteLine(args[i]);
            }
foreach 语句 
static void Main(string[] args) {
            foreach (string s in args)
            Console.WriteLine(s);
            }
break 语句 
static void Main(string[] args) {
            int i = 0;
            while (true) {
            if (i == args.Length)
            break;
            Console.WriteLine(args[i++]);
            }
            }
continue 语句 
static void Main(string[] args) {
            int i = 0;
            while (true) {
            Console.WriteLine(args[i++]);
            if (i < args.Length)
            continue;
            break;
            }
            }
return 语句 
static int F(int a, int b) {
            return a + b;
            }
            
static void Main() {
            Console.WriteLine(F(1, 2));
            return;
            }
throw 语句和 try 语句 
static int F(int a, int b) {
            if (b == 0)
            throw new Exception("Divide by zero");
            return a / b;
            }
            
static void Main() {
            try {
            Console.WriteLine(F(5, 0));
            }
            catch(Exception e) {
            Console.WriteLine("Error");
            }
            }
checked 和 unchecked 语句 
static void Main() {
            int x = Int32.MaxValue;
            Console.WriteLine(x + 1);      // Overflow
            checked {
            Console.WriteLine(x + 1);  // Exception
            }
            unchecked {
            Console.WriteLine(x + 1);  // Overflow
            }
            }
lock 语句 
static void Main() {
            A a = ...;
            lock(a) {
            a.P = a.P + 1;
            }
            }
using 语句 
static void Main() {
            using (Resource r = new Resource()) {
            r.F();
            }
            }
posted @ 2007-03-03 16:28  '.Elvis.'  阅读(421)  评论(0)    收藏  举报