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Statement
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Example
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Local variable declaration
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static void Main() {
int a;
int b = 2, c = 3;
a = 1;
Console.WriteLine(a + b + c);
}
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Local constant declaration
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static void Main() {
const float pi = 3.1415927f;
const int r = 25;
Console.WriteLine(pi * r * r);
}
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Expression statement
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static void Main() {
int i;
i = 123; // Expression statement
Console.WriteLine(i); // Expression statement
i++; // Expression statement
Console.WriteLine(i); // Expression statement
}
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if statement
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static void Main(string[]
args) {
if (args.Length == 0) {
Console.WriteLine("No arguments");
}
else {
Console.WriteLine("One or more
arguments");
}
}
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switch statement
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static void Main(string[]
args) {
int n = args.Length;
switch (n) {
case 0:
Console.WriteLine("No arguments");
break;
case 1:
Console.WriteLine("One argument");
break;
default:
Console.WriteLine("{0} arguments", n);
break;
}
}
}
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while statement
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static void Main(string[]
args) {
int i = 0;
while (i < args.Length) {
Console.WriteLine(args[i]);
i++;
}
}
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do statement
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static void Main() {
string s;
do {
s = Console.ReadLine();
if (s != null) Console.WriteLine(s);
} while (s != null);
}
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for statement
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static void Main(string[]
args) {
for (int i = 0; i < args.Length; i++) {
Console.WriteLine(args[i]);
}
}
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foreach statement
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static void Main(string[]
args) {
foreach (string s in args)
{
Console.WriteLine(s);
}
}
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break statement
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static void Main() {
while (true) {
string s = Console.ReadLine();
if (s == null) break;
Console.WriteLine(s);
}
}
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continue statement
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static void Main(string[]
args) {
for (int i = 0; i < args.Length; i++) {
if (args[i].StartsWith("/"))
continue;
Console.WriteLine(args[i]);
}
}
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goto
statement
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static void Main(string[]
args) {
int i = 0;
goto check;
loop:
Console.WriteLine(args[i++]);
check:
if (i < args.Length) goto
loop;
}
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return statement
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static int Add(int a, int
b) {
return a + b;
}
static void Main() {
Console.WriteLine(Add(1, 2));
return;
}
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yield statement
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static IEnumerable<int> Range(int from, int to) {
for (int i = from; i < to; i++) {
yield return i;
}
yield break;
}
static void Main() {
foreach (int x in Range(-10,10)) {
Console.WriteLine(x);
}
}
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throw and try
statements
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static double
Divide(double x, double y) {
if (y == 0) throw new DivideByZeroException();
return x / y;
}
static void Main(string[]
args) {
try {
if (args.Length != 2) {
throw new Exception("Two numbers required");
}
double x = double.Parse(args[0]);
double y = double.Parse(args[1]);
Console.WriteLine(Divide(x, y));
}
catch (Exception e) {
Console.WriteLine(e.Message);
}
finally {
Console.WriteLine(“Good bye!”);
}
}
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checked and unchecked
statements
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static void Main() {
int i = int.MaxValue;
checked {
Console.WriteLine(i + 1); // Exception
}
unchecked {
Console.WriteLine(i + 1); // Overflow
}
}
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lock statement
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class Account
{
decimal balance;
public void
Withdraw(decimal amount) {
lock (this) {
if (amount > balance) {
throw new Exception("Insufficient funds");
}
balance -= amount;
}
}
}
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using statement
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static void Main() {
using (TextWriter w = File.CreateText("test.txt"))
{
w.WriteLine("Line one");
w.WriteLine("Line two");
w.WriteLine("Line three");
}
}
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