Tcl 中的 嵌套语句函数

Tcl允许在另一个循环中嵌套循环。

nested loops - 语法

Tcl语言中嵌套 nested for 循环语句的语法如下-

for {initialization} {condition} {increment} {
   for {initialization} {condition} {increment} {
      statement(s);
   }
   statement(s);
}

Tcl语言中的嵌套 nested while 循环语句的语法如下-

while {condition} {
   while {condition} {
      statement(s);
   }
   statement(s);
}

nested loops - 示例

以下程序使用嵌套的for循环来查找2到100之间的质数-

#!/usr/bin/tclsh

set j 0;
for {set i 2} {$i<100} {incr i} {
   for {set j 2} {$j <= [expr $i/$j] } {incr j} {
      if {  [expr $i%$j] == 0 } {
         break
      } 
   }
   if {$j >[expr $i/$j] } {
      puts "$i is prime"
   }
}

编译并执行上述代码后，将产生以下输出-

2 is prime
3 is prime
5 is prime
7 is prime
11 is prime
13 is prime
17 is prime
19 is prime
23 is prime
29 is prime
31 is prime
37 is prime
41 is prime
43 is prime
47 is prime
53 is prime
59 is prime
61 is prime
67 is prime
71 is prime
73 is prime
79 is prime
83 is prime
89 is prime
97 is prime