Fortran - 巢狀 If 結構

您可以在其他 if 或 else if 語句內部使用一個 if 或 else if 語句。

語法

巢狀 if 語句的語法如下所示 −

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

示例

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

編譯並執行上述程式碼時，它會生成以下結果 −

Value of a is 100 and b is 200
exact value of a is 100
exact value of b is 200