嵌套 if 语句（nested if statements）

在D编程中nest if-else语句总是合法的，这意味着你可以在另一个if或else if语句中使用if或else if语句。

语法 (Syntax)

nested if语句的语法如下 -

if( boolean_expression 1) { 
   /* Executes when the boolean expression 1 is true */ 
   if(boolean_expression 2) { 
      /* Executes when the boolean expression 2 is true */
   }
}

您可以使用与嵌套if语句类似的方式嵌套if else if...else 。

例子 (Example)

import std.stdio;
int main () { 
   /* local variable definition */ 
   int a = 100; 
   int b = 200; 
   /* check the boolean condition */ 
   if( a == 100 ) { 
      /* if condition is true then check the following */ 
      if( b == 200 ) { 
         /* if condition is true then print the following */ 
         writefln("Value of a is 100 and b is 200" ); 
      } 
   } 
   writefln("Exact value of a is : %d", a ); 
   writefln("Exact value of b is : %d", b ); 
   return 0; 
}

编译并执行上述代码时，会产生以下结果 -

Value of a is 100 and b is 200 
Exact value of a is : 100 
Exact value of b is : 200