07_ABAP - Common Control Statements

7/30/2019 07_ABAP - Common Control Statements

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ABAP - Common Control

Statements


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Contents

Objectives

Control Statements

Using the IF Statement

Using the CASE Statement

Using the EXIT Statement

Using the DO Statement

Using the WHILE Statement

Using the CONTINUE Statement

Using the CHECK Statement

Comparing the EXIT, CONTINUE, and CHECK Statements

Simple Position and Length Specifications for the WRITE Statement

Summary

Q&A


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Contents

Objectives


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Objectives

Code the common control statements IF,

CASE, DO, and WHILE

Control program sequence using EXIT,CONTINUE, and CHECK

Code simple position and length specificationson the WRITE statement


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Contents

Using the IF Statement


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IF Statement

Syntax: if [not] exp [ and [not] exp ] [ or [not] exp ].

---

[elseif exp.

---][else.

---]

endif.

where: exp is a logical expression that evaluates to a true or false

condition.

--- represents any number of lines of code. Even zero lines areallowed.


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IF Statement


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IF Statement

Data Conversion of Literals During Comparisons


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IF Statement

REPORT y_vu_1001.

DATA: BEGIN OF s1,x VALUE 'X',

y VALUE 'Y',

z VALUE 'Z',

END OF s1,

BEGIN OF s2,

x VALUE 'X',

z VALUE 'Z',

END OF s2.

IF s1-x = s2-x.

WRITE: / s1-x, '=', s2-x.

ELSE.

WRITE: / s1-x, '', s2-x.

ENDIF.

IF s1-x BETWEEN s2-x AND s2-z.

WRITE: / s1-x, 'is between', s2-x, 'and', s2-z.

ELSE.

WRITE: / s1-x, 'is not between', s2-x, 'and', s2-z.

ENDIF.

IF s1 = s2. "comparing field strings byte by byte

WRITE: / 's1 = s2'.

ELSE.

WRITE: / 's1 s2'.

ENDIF.

IF 0 = ' '. "Watch out for this one

WRITE: / '0 = '' '''.

ELSE.

WRITE: / '0 '' '''.

ENDIF.


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Using ELSEIF

to avoid nesting IFs

IF f1 = f2.

WRITE: / f1, '=', f2.

ELSEIF f1 = f3.

WRITE: / f1, '=', f3.ELSEIF f2 = f3.

WRITE: / f2, '=', f3.

ELSE.

WRITE: / 'all fields are different'.

ENDIF.

IF f1 = f2.

WRITE: / f1, '=', f2.

ELSE.

IF f1 = f3.WRITE: / f1, '=', f3.

ELSE.

IF f2 = f3.

WRITE: / f2, '=', f3.

ELSE.

WRITE: / 'all fields are different'.

ENDIF.ENDIF.

ENDIF.


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Character String Operators


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Character String Operators

'AABB' co 'AB'

'ABCD' co 'ABC'

'AABB' cn 'AB'

'ABCD' cn 'ABC'

'AXCZ' ca 'AB'

'ABCD' ca 'XYZ'

'AXCZ' na 'ABC'

'ABCD' na 'XYZ'

True

False

False

True

True

False

False

True


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CP contains pattern


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Contents

Using the CASE Statement


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CASE Statement

Syntax: case v1.

when v2 [ or vn ... ].

---

when v3 [ or vn ... ].---

[ when others.

--- ]

endcase.

where: v1 or v2 can be a variable, literal, constant, or field string.

--- represents any number of lines of code. Even zero lines areallowed.


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CASE Statement

REPORT y_vu_1005.

PARAMETERS f1 TYPE i DEFAULT 2.

CASE f1.

WHEN 1. WRITE / 'f1 = 1'.

WHEN 2. WRITE / 'f1 = 2'.WHEN 3. WRITE / 'f1 = 3'.

WHEN OTHERS. WRITE / 'f1 is not 1, 2, or 3'.

ENDCASE.


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Contents

Using the EXIT Statement


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EXIT Statement

Syntax: exit.

prevents further processing from occurring

in main program: exits program

inside LOOP, SELECT, DO, WHILE: leaves loop processing

inside subroutine: leaves subroutine

REPORT y_vu_1006.

WRITE: / 'This line is showed.'.EXIT.

WRITE: / 'This line is not showed.'.


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Contents

Using the DO Statement


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DO Statement

Syntax:

do [ v1 times ]

---

[exit.]---

enddo.

where: v1 is a variable, literal, or constant.

SY-INDEX: the current iteration number


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DO Statement

sy-index = 99.

WRITE: / 'before loop, sy-index =', sy-index, / ''.DO 5 TIMES.

WRITE sy-index.

ENDDO.

WRITE: / 'after loop, sy-index =', sy-index, / ''.

DO 4 TIMES.

WRITE: / 'outer loop, sy-index =', sy-index.DO 3 TIMES.

WRITE: / ' inner loop, sy-index =', sy-index.

ENDDO.

ENDDO.

WRITE: / ''. "new line

DO 10 TIMES.WRITE sy-index.

IF sy-index = 3.

EXIT.

ENDIF.

ENDDO.


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Contents

Using the WHILE Statement


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WHILE Statement

similar to DO statement

Syntax:

while exp.

---

[ exit. ]

---

endwhile. where:

exp is a logical expression.


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Contents

Using the CONTINUE

Statement


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CONTINUE Statement

only within a loop

terminates the current loop pass

jumps to the beginning of the next loop pass

DO 10 TIMES.

IF sy-index BETWEEN 3 AND 8.CONTINUE.

ENDIF.

WRITE sy-index.

ENDDO.


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Contents

Using the CHECK Statement


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CHECK Statement

Syntax: CHECK exp.

within a loop

If exp is TRUE: does nothing

If exp is FALSE: same as CONTINUE

terminates the current loop pass

jumps to the beginning of the next loop pass

DO 10 TIMES.

CHECK NOT sy-index BETWEEN 3 AND 8.

WRITE sy-index.

ENDDO.


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Contents

Comparing the EXIT,

CONTINUE, and CHECK

Statements


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Comparing EXIT, CONTINUE, and

CHECK


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Contents

Simple Position and Length

Specifications for the WRITE

Statement


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WRITE Statement

Syntax:

write [/][P][(L)] v1.

where:

v1 is a variable, literal, or constant.

P is a number indicating a position on the current

line of output.

L is a number indicating the number of bytesallocated in the list for outputting v1.


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WRITE Statement


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WRITE Statement

WRITE: / '....+....1....+....2....+....3....+....4',

/1 'Hi', 4 'There',

/1 'Hi', 3 'There',

/1 'Hi', 2 'There',

/1 'Hi', 1 'There',/2 'Hi', 'There',

/2(1) 'Hi', 'There',

/2(3) 'Hi', 'There',

/2 'Hi', 10(3) 'There'.

....+....1....+....2....+....3....+....4

Hi There

HiThere

HThere

There

Hi There

H There

Hi There

Hi The


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Contents

Summary


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Summary

Comparison statements: IF and CASE CASE: compares 2 values only and only for equality Conversions occur when comparing differing data types string comparisons

CP and NP to match strings against patterns

SY-FDPOS is set after each comparison Loop statements: DO and WHILE

SY-INDEX: contains the counter for the current loop pass

EXIT, CONTINUE, and CHECK statements: to modify loopprocessing.

EXIT: leaves the current loop. CONTINUE: unconditional jump to the end of the loop CHECK exp: jumps to the end of the loop ifexp is false

WRITE statement: position and length


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Summary

Documents

07_ABAP - Common Control Statements