Introduction to QBASIC
Control Statement
Branching Statement
Looping Statement
Library Function
Array in QBASIC
Modular Programming
File Handling
Introduction to QBASIC
Introduction to QBasic Elements of QBASIC Operators in QBASIC Qbasic Statements
Control Statement
Control Statements in QBASIC
Branching Statement
IF ... THEN Statement IF ... THEN .... ELSE Statement IF ... THEN ... ELSEIF Statement SELECT CASE Statement GOTO Statement
Looping Statement
Introduction FOR ... NEXT Loop WHILE .... WEND DO ... LOOP Nested Loop in QBASIC
Library Function
Library Function in QBASIC Mathematical Library Functions (QBASIC) String Library Functions (QBASIC)
Array in QBASIC
Array in QBASIC
Modular Programming
Concept of Modular Programming SUB Procedure (QBASIC) FUNCTION Procedure (QBASIC)
File Handling
File Handling (QBASIC)

DO ... LOOP

It is another type of looping statement in QBASIC. Sometime it is also called DO WHILE LOOP. In this loop, the instructions within the loop are performed if the comparison is true. We can use this loop by 4 different methods. Syntax are given below.

Syntax 1 
DO ... WHILE 
   [statements] 
LOOP
Syntax 2 
DO 
  [statements] 
LOOP WHILE
Syntax 3 
DO ... UNTIL 
  [statement]   
LOOP
Syntax 4 
DO 
  [statement] 
LOOP UNTIL

While writing a program we can fallow any one syntax among them.

Example 1

WAP to print the natural numbers from 1 to 10

CLS
CLS
n = 1
DO
    PRINT n;
    n = n + 1
LOOP WHILE n <= 10
END

Example 2

WAP to print even numbers from 1 to 20

CLS
n = 2
DO
    PRINT n;
    n = n + 2
LOOP WHILE n <= 20
END

Example 3

WAP to print the numbers from 20 to 1 in descending order.

CLS
n = 20
DO
    PRINT n;
    n = n - 1
LOOP UNTIL n < 1
END

Example 4

WAP to print your name 10 times

CLS
n = 1
DO WHILE n <= 10
    PRINT "Your Name"
    n = n + 1
LOOP
END

Example 5

WAP to print the multiplication table of given number.

CLS
i = 1
INPUT "Enter any number "; n
DO WHILE i <= 10
    PRINT n; "x"; i; "="; i * n
    i = i + 1
LOOP
END

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