Programming Logic Pseudocode Structures

Structure	Pseudocode Format	Example
Sequence One statement or structure follows another	Statement 1 Statement 2 . . statement n	Total = 0 Add 1 to COUNT Flag = ‘YES’ . .
Decision IF-THEN or IF-THEN-ELSE	IF condition(s) Statement(s) to be executed for TRUE ENDIF IF condition(s) Statement(s) to be executed for TRUE ELSE Statement(s) to be executed for FALSE ENDIF	IF SALES > 2000 Add 1 to COUNT Add SALES to TOTAL ENDIF IF EOF or COUNT > 500 FLAG = ‘YES’ ELSE DO Process-Procedure ENDIF
Loops DO-WHILE or DO-UNTIL	DO loop-name WHILE condition(s) Statement(s) to be repeated while condition is TRUE ENDO DO loop-name UNTIL condition(s) Statement(s) to be repeated until condition is TRUE ENDO	DO Detail-Loop WHILE not EOF Print Name Read Name, Amount ENDO DO Search-Loop UNTIL (EOF or I > 500) READ DATA IF not EOF IF DATA = SEARCH-DATA PRINT “Found!” FLAG = ‘YES’ ENDIF ENDIF ENDO
Case For 3 or more alternatives to one decision	CASE data field WHEN condition-1 Statement(s)-1 to be executed WHEN condition-2 Statement(s)-2 to be executed WHEN condition-3 Statement(s)-3 to be executed ELSE Default statement(s) ENDCASE	CASE room type WHEN single Price = $105 WHEN double Price = $85 WHEN family Price = $65 ELSE Print “Invalid Room Type” ENDCASE

Pseudocode Rules

1. The main program is a sequence structure at the left margin headed by START and terminated by STOP.

2. Each IF is terminated by an ENDIF. IF, ELSE, and ENDIF are placed at the same margin.

3. Each DO containing embedded statements is terminated by an ENDO.

4. Statements belonging to an IF, ELSE, or DO are indented between the heading and the corresponding END scope-terminator to make the pseudocode easy to read and understand.

5. Pseudocode is language-independent – avoid the use of words peculiar to a specific programming language.

6. While punctuation (such as terminating an instruction) is optional, uppercase is suggested for keywords: IF, ELSE, DO, END-terminators, WHILE, UNTIL, START, and STOP.