break（C# 参考）
break 语句用于终止最近的封闭循环或它所在的 switch 语句。控制传递给终止语句后面的语句（如果有的话）。
示例
在此示例中，条件语句包含一个应从 1 计数到 100 的计数器；但 break 语句在计数器计数到 4 后终止了循环。
class BreakTest
{
static void Main()
{
for (int i = 1; i <= 100; i++)
{
if (i == 5)
{
break;
}
Console.WriteLine(i);
}
// Keep the console open in debug mode.
Console.WriteLine("Press any key to exit.");
Console.ReadKey();
}
}
/*
Output:
1
2
3
4
*/
在此示例中，break 语句用于中断内层嵌套循环，并将控制权返回给外层循环。
class BreakInNestedLoops
{
static void Main(string[] args)
{
int[] numbers = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
char[] letters = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j' };
// Outer loop
for (int x = 0; x < numbers.Length; x++)
{
Console.WriteLine("num = {0}", numbers[x]);
// Inner loop
for (int y = 0; y < letters.Length; y++)
{
if (y == x)
{
// Return control to outer loop
break;
}
Console.Write(" {0} ", letters[y]);
}
Console.WriteLine();
}
// Keep the console open in debug mode.
Console.WriteLine("Press any key to exit.");
Console.ReadKey();
}
}
/*
* Output:
num = 0
num = 1
a
num = 2
a b
num = 3
a b c
num = 4
a b c d
num = 5
a b c d e
num = 6
a b c d e f
num = 7
a b c d e f g
num = 8
a b c d e f g h
num = 9
a b c d e f g h i
*/
下面的示例演示 break 在 switch 语句中的用法。
class Switch
{
static void Main()
{
Console.Write("Enter your selection (1, 2, or 3): ");
string s = Console.ReadLine();
int n = Int32.Parse(s);
switch (n)
{
case 1:
Console.WriteLine("Current value is {0}", 1);
break;
case 2:
Console.WriteLine("Current value is {0}", 2);
break;
case 3:
Console.WriteLine("Current value is {0}", 3);
break;
default:
Console.WriteLine("Sorry, invalid selection.");
break;
}
// Keep the console open in debug mode.
Console.WriteLine("Press any key to exit.");
Console.ReadKey();
}
}
/*
Sample Input: 1
Sample Output:
Enter your selection (1, 2, or 3): 1
Current value is 1
*/
如果输入了 4，则输出为：
Enter your selection (1, 2, or 3): 4
Sorry, invalid selection.
C# 语言规范
有关更多信息，请参见 C# 语言规范。该语言规范是 C# 语法和用法的权威资料。