Statements

C# borrows most of its statements directly from C and C++, though there are some noteworthy additions and modifications. The table below lists the kinds of statements that can be used, and provides an example for each. Statement Example Statement lists and block statements static void Main() { F(); G(); { H(); I(); } } Labeled statements and goto statements static void Main(string[] args) { if (args.Length == 0) goto done; Console.WriteLine(args.Length); done: Console.WriteLine("Done"); } Local constant declarations static void Main() { const float pi = 3.14f; const int r = 123; Console.WriteLine(pi * r * r); } Local variable declarations static void Main() { int a; int b = 2, c = 3; a = 1; Console.WriteLine(a + b + c); } Expression statements static int F(int a, int b) { return a + b; } static void Main() { F(1, 2); // Expression statement } if statements static void Main(string[] args) { if (args.Length == 0) Console.WriteLine("No args"); else Console.WriteLine("Args"); } switch statements 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 statements static void Main(string[] args) { int i = 0; while (i < args.Length) { Console.WriteLine(args[i]); i++; } } do statements static void Main() { string s; do { s = Console.ReadLine(); } while (s != "Exit"); } for statements static void Main(string[] args) { for (int i = 0; i < args.Length; i++) Console.WriteLine(args[i]); } foreach statements static void Main(string[] args) { foreach (string s in args) Console.WriteLine(s); } break statements static void Main(string[] args) { int i = 0; while (true) { if (i == args.Length) break; Console.WriteLine(args[i++]); } } continue statements static void Main(string[] args) { int i = 0; while (true) { Console.WriteLine(args[i++]); if (i < args.Length) continue; break; } } return statements static int F(int a, int b) { return a + b; } static void Main() { Console.WriteLine(F(1, 2)); return; } throw statements and try statements 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 and unchecked statements 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 statements static void Main() { A a = ...; lock(a) { a.P = a.P + 1; } } using statements static void Main() { using (Resource r = new Resource()) { r.F(); } }