While Loop

While statement of do while loop, a stmt node.

Declaration

Syntax

WhileLoop(expr test, stmt* body)

Arguments

test contains expression to be tested. body contains 0 or more statements or constructs.

Return values

None.

Description

While statement of do while loop constitues test expression to be evaulated at each run on the while statement, and after first run.

Execution proceeds as:

1. The specified expression is evaluated.

2. If the value of the expression is true, the statements in the range of the DO WHILE loop are executed.

3. If the value of the expression is false, control is transferred to the statement following the DO WHILE loop.

Types

Expression and pointer to body of the DO WHILE loop.

Examples

program while
implicit none
integer :: i, j
i = 1
j = 0
do while (i < 11)
    j = j + i
    i = i + 1
end do
if (j /= 55) error stop
if (i /= 11) error stop
end

ASR:

(TranslationUnit
    (SymbolTable
        1
        {
            while_01:
                (Program
                    (SymbolTable
                        2
                        {
                            i:
                                (Variable
                                    2
                                    i
                                    Local
                                    ()
                                    ()
                                    Default
                                    (Integer 4 [])
                                    Source
                                    Public
                                    Required
                                    .false.
                                ),
                            j:
                                (Variable
                                    2
                                    j
                                    Local
                                    ()
                                    ()
                                    Default
                                    (Integer 4 [])
                                    Source
                                    Public
                                    Required
                                    .false.
                                )

                        })
                    while_01
                    []
                    [(=
                        (Var 2 i)
                        (IntegerConstant 1 (Integer 4 []))
                        ()
                    )
                    (=
                        (Var 2 j)
                        (IntegerConstant 0 (Integer 4 []))
                        ()
                    )
                    (WhileLoop
                        (IntegerCompare
                            (Var 2 i)
                            Lt
                            (IntegerConstant 11 (Integer 4 []))
                            (Logical 4 [])
                            ()
                        )
                        [(=
                            (Var 2 j)
                            (IntegerBinOp
                                (Var 2 j)
                                Add
                                (Var 2 i)
                                (Integer 4 [])
                                ()
                            )
                            ()
                        )
                        (=
                            (Var 2 i)
                            (IntegerBinOp
                                (Var 2 i)
                                Add
                                (IntegerConstant 1 (Integer 4 []))
                                (Integer 4 [])
                                ()
                            )
                            ()
                        )]
                    )
                    (If
                        (IntegerCompare
                            (Var 2 j)
                            NotEq
                            (IntegerConstant 55 (Integer 4 []))
                            (Logical 4 [])
                            ()
                        )
                        [(ErrorStop
                            ()
                        )]
                        []
                    )
                    (If
                        (IntegerCompare
                            (Var 2 i)
                            NotEq
                            (IntegerConstant 11 (Integer 4 []))
                            (Logical 4 [])
                            ()
                        )
                        [(ErrorStop
                            ()
                        )]
                        []
                    )]
                )

        })
    []
)

See Also