Fortran - 嵌套 If 构造

  • 简述

    你可以使用一个 if 或者 else if 另一个里面的声明 if 或者 else if 声明。
  • 句法

    嵌套的语法if声明如下 -
    
    if ( logical_expression 1) then
       !Executes when the boolean expression 1 is true 
       …
       
       if(logical_expression 2)then 
          ! Executes when the boolean expression 2 is true 
          …
       end if
    end if
    
  • 例子

    
    program nestedIfProg
    implicit none
       ! local variable declaration
       integer :: a = 100, b= 200
     
       ! check the logical condition using if statement
       if( a == 100 ) then
      
       ! if condition is true then check the following 
          
       if( b == 200 ) then
      
       ! if inner if condition is true 
       print*, "Value of a is 100 and b is 200" 
      
       end if
       end if
       
       print*, "exact value of a is ", a
       print*, "exact value of b is ", b
     
    end program nestedIfProg
    
    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