Qbasic looping with sub procedure

 

 

QBasic is an interpreted programming language that was widely used in the 1980s and 1990s. One of the most important features of QBasic is its looping capability, which allows programmers to execute a set of statements repeatedly until a certain condition is met. In this article, we will discuss QBasic looping with sub procedure, which is a powerful technique to enhance code readability and maintainability.

Sub procedure in QBasic

Before we dive into looping with sub procedure, let's discuss what sub procedure are in QBasic. Sub..End sub also called subroutine. It is also known as procedures or functions, are self-contained blocks of code that perform a specific task. Sub procedure allow programmers to break down a large program into smaller, more manageable pieces. In QBasic, sub procedure are declared using the "SUB" keyword, followed by the subroutine name and any necessary parameters, and then ended with the "END SUB" keyword.

Here is an example of a sub procedurein QBasic:

SUB PrintMessage(Message AS String)

  PRINT Message

END SUB

 

Above subroutine, named "PrintMessage," takes one parameter, "Message," which is a string that will be printed to the console when the subroutine is called. To call this subroutine from another part of the program, you would simply use the subroutine name followed by the necessary arguments, like this:

PrintMessage("Hello, world!")

This would output the message "Hello, world!" to the console.

 

Qbasic Looping with Sub procedure

Now, that we understand sub procedure in QBasic, let's move on to looping with Sub..End Sub or sub procedure. The basic idea is to encapsulate the looping code inside a sub..end sub or sub procedure, which can be called from anywhere in the program. This can make the code more modular and easier to read and

maintain.

Here is an example of a simple loop sub procedure that prints the numbers 1 through 10 to the console:

SUB PrintNumbers()

FOR i = 1 TO 10

PRINT i

NEXT i

END SUB

This subroutine, named "PrintNumbers," uses a "FOR" loop to iterate from 1 to 10 and print each number to the console. To call this subroutine from another part of the program, you would simply use the subroutine name, like this:

PrintNumbers()

This would output the numbers 1 through 10 to the console.

Looping in qbasic

 

A loop is defined as a set of instructions that allows us to repeat the block of statements to the given number of times or till the given condition is satisfied or until a certain condition becomes true. Programming process jumps forward and backward in looping. Iteration is another name for looping.

Every loop statement requires following terms:

Counter:

A counter is a variable which controls the loop statement and provides the track to run the loop statement in certain number of times.

 

Initial Value:

The starting value of a loop statement is called initial value. Initial value may be negative, zero or positive.

 

Sentinel Value:

The final (last) value of loop statement after which the loop will terminate.

 

Step Value:

Step value is used to modify the value of counter by a certain amount. If initial value is greater than sentinel value, step value will be negative. If initial value is less than sentinel value, step value will be positive. Step value never be neutral or zero.

 

Accumulator:

Accumulator is a numeric variable which accumulate the values in a loop statement.

 

Following are the different types of looping in qbasic

i) FOR……NRXT

ii) WHILE……WEND

iii) DO……LOOP

 

FOR…NEXT 

It is a controlled looping statement in which the statements are executed for a given number of times. The FOR….NEXT looping uses a variable called counter that modifies the value during each repetition of the loop.

The loop is executed with the loop control variable at initial value to final value and the values in between.

Syntax:           

FOR COUNTER = START  TO END [STEP value]

[statements]

NEXT

 

Where,

COUNTER is a numeric variable used as a loop counter. It is also called control variable.

START is a initial value of the counter variable.

END is the final or sentinel value of the counter variable.

STEP is an optional which is used to incensement or decrement the value of counter variable by a certain value.

 

Example: CLS REM program to display the natural number from 1 to 5 vertically FOR x = 1 TO 5 PRINT x NEXT x END

Output: 1 2 3 4 5

Note: Use (;) in print statement to display the result in horizontally.

 

WHILE…..WEND

It is a loop statement that executes a series of statement in a loop as long as a given condition is true.

Syntax:

WHILE <condition>

[statement blocks]

………………..

WEND

Where,

Condition it is any Boolean expression that gives true or false as result.

Statement block are the list of statements that will be executed if the condition is true.

 

Example: 1

CLS

REM program to display the natural number from 1 to 50 vertically

x = 1

WHILE x <= 50

PRINT x

x = x + 1

WEND

END

 

DO ……LOOP

It is a loop statement that repeats a block of statement while a condition is true or until a condition becomes true. This loop statement can execute either WHILE or UNTIL condition becomes true

Syntax: 1 DO [{WHILE|UNTIL} <condition>] [statement blocks] LOOP

Syntax: 2 DO [Statement blocks] LOOP [{WHILE|UNTIL} <condition> ]

 

Example:1 Using DO WHILE …..LOOP REM program to display the natural number from 1 to 10 CLS x = 1 DO WHILE x <= 10 PRINT x x = x + 1 LOOP END

Example: 2 Using: DO UNTIL ……LOOP REM program to display the natural number from 1 to 10 CLS x = 1 DO UNTIL x > 10 PRINT x x = x + 1 LOOP END

 

 

Solved examples of qbasic looping with sub procedure

 

1. WAP to display the series of number from 1 to 10.

DECLARE SUB ser( )

CLS

CALL ser

END

SUB ser

FOR x= 1 to 10

PRINT x

NEXT x

END SUB

 

2. WAP to print the following serial 9,7,5…….1  (SLC 2065 )

DECLARE SUB series( )

CALL series

END

 

SUB series

FOR n= 9 to 1 STEP -2

PRINT n;

NEXT n

 

3. WAP to display the even number from 2 to 20 and their sum.

DECLARE SUB sum( )

CLS

CALL sum

END

SUB sum

FOR x= 2 to 20 STEP 2

PRINT x

s=s+x

NEXT x

PRINT s

 

4. WAP to display the series like 5 55 555 5555 55555.

DECLARE SUB ser( )

CLS

CALL ser

END

SUB ser

a=5

FOR x= 1 to 5

PRINT a;

a=(a*10)+5

NEXT x

END SUB

 

5. WAP to display the series like 55555  5555 555 55 5

DECLARE SUB ser( )

CLS

CALL ser

END

SUB ser

a=55555

x=1

WHILE x<=5

PRINT a;

a=a\10

x=x+1

WEND

 

6. WAP to display the “BASIC” 50 times on the screen

DECLARE SUB basic(a$)

CLS

a$= “QBASIC”

CALL basic(a$)

END

SUB basic(a$)

FOR x= 1 to 50

PRINT a$

NEXT

END SUB

 

7. WAP to display the series 1,8,27…… till 10th term.

DECLARE SUB out( )

CLS

CALL out

END

SUB out

x=1

WHILE x<=10

PRINT x^3

x=x+1

WEND

END SUB

 

8. WAP to display the series 2,8,18,32….10th term.

DECLARE SUB ser( )

CLS

CALL ser

END

 

SUB ser

FOR x= 1 to 10

PRINT (x^2)*2;

NEXT x

END SUB

 

9. WAP to display the series 1,8,27,……10^th term.

DECLARE SUB ser( )

CLS

CALL ser

END

SUB ser

a=1

DO

PRINT a^3

a=a+1

LOOP WHILE a<=10

END SUB

 

10 Write a program using to display given series up to 15^th term 525, 500, 475, 450

DECLARE SUB ser ()

CLS

CALL ser

END

SUB ser

a = 525

FOR x = 1 TO 15

PRINT a;

a = a - 25

NEXT x

END SUB

 

11. WAP to display the series as : 5 6 9 14 21 30

DECLARE SUB ser( )

CLS

CALL ser

END

SUB ser

a=5: b=1

PRINT a;

FOR x= 1 to 5

c=a+b

PRINT c;

a=c

b=b+2

NEXT x

END SUB

 

12. WAP to display the series as 8 18 32 50 72 98……. 10^th term

DECLARE SUB ser( )

CLS

CALL ser

END

SUB ser

a=2: b=6

FOR x= 1 to 10

c=a+b

PRINT c;

a=c

b=b+4

NEXT x

END SUB

 

13. WAP to display the series as 3 12 27 ……10^th term.

DECLARE SUB ser( )

CLS

CALL ser

END

SUB ser

a=3

FOR x= 1 to 10

PRINT a*x;

a=a+3

NEXT x

END SUB

 

14. WAP to display the multiplication table of 5.

DECLARE SUB mul( )

CLS

CALL mul

END

SUB mul

a=5

FOR x= 1 to 10

PRINT a; "X"; x; "=";a*x

NEXT x

END SUB

 

15. Write a program using a SUB procedure module to print the multiplication table of any input number up to 10th term. (SEE 2075 State 2)

DECLARE SUB MUL (N)

CLS

INPUT "ENTER ANY NUMBER"; N

CALL MUL (N)

END

 

SUB MUL (N)

FOR I = 1 TO 10

PRINT N; "X"; I; "="; N * I

NEXT I

END SUB

 

16. WAP to input any string from the user and display it in reverse order. (SEE 2072)

DECLARE SUB r(w$)

CLS

INPUT "Enter any string:-";w$

CALL r(w$)

END

SUB r(w$)

FOR x= LEN(w$) to 1 STEP -1

PRINT MID$(w$,x,1);

NEXT x

END SUB

 

17. WAP to display all the vowel letters from the input string.

DECLARE SUB COUNT (S$)

CLS

INPUT "ENTER ANY STRING"; S$

CALL COUNT(S$)

END

 

SUB COUNT (S$)

FOR I = 1 TO LEN(S$)

B$ = MID$(S$, I, 1)

C$ = UCASE$(B$)

IF C$ = "A" OR C$ = "E" OR C$ = "I" OR C$ = "O" OR C$ = "U" THEN PRINT C$

NEXT I

END SUB

 

 

18. WAP to print the total number of vowel alphabets present in the given word.  (SEE 2075)

DECLARE SUB COUNT (S$)

CLS

INPUT "ENTER ANY STRING"; S$

CALL COUNT(S$)

END

 

SUB COUNT (S$)

VC = 0

FOR I = 1 TO LEN(S$)

B$ = MID$(S$, I, 1)

C$ = UCASE$(B$)

IF C$ = "A" OR C$ = "E" OR C$ = "I" OR C$ = "O" OR C$ = "U" THEN

VC = VC + 1

END IF

NEXT I

PRINT "TOTAL NO. OF VOWELS= "; VC

END SUB

 

19. WAP to display only consonant letters from the given string.

DECLARE SUB test ()

CLS

CALL test

END

SUB test

INPUT "enter any string"; w$

p$ = UCASE$(w$)

FOR x = 1 TO LEN(p$)

m$ = MID$(p$, x, 1)

IF m$ <> "A" AND m$ <> "E" AND m$ <> "I" AND m$ <> "O" AND m$ <> "U" THEN PRINT m$

NEXT

END SUB

 

20. WAP to count total numbers of consonant letters from input string.

DECLARE SUB test ()

CLS

CALL test

END

SUB test

INPUT "enter any string"; w$

p$ = UCASE$(w$)

FOR x = 1 TO LEN(p$)

m$ = MID$(p$, x, 1)

IF m$ <> "A" AND m$ <> "E" AND m$ <> "I" AND m$ <> "O" AND m$ <> "U" THEN c=c+1

NEXT

PRINT “Total consonant letters”;c

END SUB

 

21 . WAP to input any string from the keyboard and display whether that string is     palindrome or not example of palindrome is LIRIL. It is same from left to right and right to left.

DECLARE SUB p(w$)

CLS

INPUT "Enter any string:";w$

CALL p(w$)

END

SUB p(w$)

FOR x= LEN(w$) to 1 STEP -1

m$=m$+MID$(w$,x,1)

NEXT x

IF w$=m$ THEN

PRINT "Palindrome"

ELSE

PRINT "Not Palindrome"

ENDIF

END SUB

 

22.    WAP to input any string from the keyboard and display how many words are available in string.  (SEE 2074)

DECLARE SUB word(w$)

CLS

INPUT "Enter any string:";w$

CALL word(w$)

w=1

FOR x= 1 to LEN(w$)

m$=MID$(w$,x,1)

IF m$=" " THEN

w=w+1

ENDIF

NEXT x

PRINT "Total no of words=";w

END SUB

 

 

23.    WAP to input any word from the keyboard and count total occurrences of the character R ignoring uppercase and lowercase.

DECLARE SUB res ()

CLS

CALL res

END

SUB res

CLS

INPUT "enter any sentence="; a$

INPUT "Enter the character which you want to count.="; b$

FOR x = 1 TO LEN(a$)

c$ = MID$(a$, x, 1)

IF b$ = c$ THEN r = r + 1

NEXT x

PRINT "Total no of character available="; r

END SUB

 

24.    WAP to input your full name and display initial letters.  Eg. If you input name as  Govind Prasad Joshi the initial letters are G.P. Joshi

DECLARE SUB nam ()

CLS

CALL nam

END

SUB nam

INPUT "Enter your name="; n$

FOR x = 1 TO LEN(n$)

IF MID$(n$, x, 1) = " " THEN

PRINT MID$(n$, p + 1, 1); ".";

p = x

END IF

NEXT x

PRINT RIGHT$(n$, LEN(n$) - p)

END SUB

 

25. Write a program to print input string in alternate capital. Eg. CoMpUtEr

DECLARE SUB mysub(a$)

CLS

INPUT “Enter a number”; a$

CALL mysub(a$)

END

SUB mysub(a$)

FOR i = 1 to len(a$)

b$= mid$(a$,i,1)

c= i MOD 2

IF c<>0 THEN c$=UCASE(b$)

ELSE

c$=LCASE(b$)

ENDIF

d$=d$+c$

NEXT i

PRINT d$

END SUB

 

26. WAP print the fibbonies series 1,1,2,3,5,8…..upto ten terms. (SLC 2069)

DECLARE SUB fibo ()

CLS

CALL fibo

END

SUB fibo

a = 1

b = 1

FOR i = 1 TO 5

PRINT a; b;

a = a + b

b = a + b

NEXT

 

27.  WAP to input any digit and display its sum. (Example: If user inputs digit 123 then  output will be 1+2+3=6]

DECLARE SUB sum ()

CLS

CALL sum

END

 

SUB sum

INPUT "enter any no"; n

WHILE n <> 0

r = n MOD 10

s = s + r

n = n \ 10

WEND

PRINT s

END SUB

 

 

28.    WAP to display the input digit in reverse order. (Example: if user input digit 123  then output will be 321)

DECLARE SUB sum ()

CLS

CALL sum

END

 

SUB sum

INPUT "enter any no"; n

WHILE n <> 0

r = n MOD 10

s = s * 10 + r

n = n \ 10

WEND

PRINT s

END SUB

 

29.  WAP to check whether input digit is palindrome or not. (Palindrome is the digit that looks like same from both side)

DECLARE SUB sum ()

CLS

CALL sum

END

 

SUB sum

INPUT "enter any no"; n

m = n

WHILE n <> 0

r = n MOD 10

s = s * 10 + r

n = n \ 10

WEND

IF m = s THEN

PRINT "Digit is palindrome"

ELSE

PRINT "Digit is not palindrome"

END IF

END SUB

 

 30. WAP to check whether input digit is Armstrong or not. (An Armstrong number of three digits is an integer such that the sum of the cubes of its digits is equal to the number itself. For example: 371 is an Armstrong number since 3^3+7^3+1^3=371)

DECLARE SUB arm ()

CLS

CALL arm

END

 

SUB arm

INPUT "enter any digit"; n

m = n

WHILE n <> 0

r = n MOD 10

s = s + r ^ 3

n = n \ 10

WEND

IF s = m THEN

PRINT "Armstrong number"

ELSE

PRINT "not Armstrong number"

END IF

END SUB

 

31. WAP to find the product of the digits of the given number.

DECLARE SUB PD(N)

CLS

INPUT "Enter a Number";N

CALL PD(N)

END

SUB PD(N)

R = 1

WHILE N<>0

A = N MOD 10

R = R * A

N = FIX ( N / 10 )

WEND

PRINT "Product of Digit is";R

END SUB

 

32. Write a program that displays factorial of an input number using

DECLARE SUB FACT(N)

CLS

INPUT “ENTER ANY NUMBER”;N

CALL FACT(N)

END

SUB FACT(N)

F=1

FOR I = 1 TO N

F=F*I

NEXT I

PRINT “FACTORIAL OF”;N;”=”;F

END SUB

 

33. WAP to input any number and display whether input number is prime or composite.

DECLARE SUB prime ()

CLS

CALL prime

END

SUB prime

INPUT "enter any no"; n

c = 0

FOR x = 1 TO n

IF n MOD x = 0 THEN c = c + 1

NEXT

IF c = 2 THEN

PRINT "prime no"

ELSE

PRINT "Composite no"

ENDIF

END SUB

 

 

34. WAP to display the sum of even digit of input digit.

DECLARE SUB SUMEVEN (N)

CLS

INPUT "ENTER ANY NUMBER"; N

CALL SUMEVEN(N)

END

SUB SUMEVEN (N)

S = 0

WHILE N <> 0

R = N MOD 10

IF R MOD 2 = 0 THEN S = S + R

N = N \ 10

WEND

PRINT "SUM OF EVEN DIGITS"; S

END SUB

 

Conclusion

In this blog post, we discussed QBasic looping with sub procedure, which is a powerful technique to enhance code readability and maintainability. We also discussed sub procedure in QBasic, which are self-contained blocks of code that perform a specific task. Subroutines or sub procedures allow programmers to break down a large program into smaller, more manageable pieces.

We learned about different types of looping in QBasic, such as FOR…NEXT, WHILE…WEND, and DO…LOOP. We also saw examples of each of these looping structures.

In summary, QBasic looping with sub procedure is an essential technique for any QBasic programmer. It helps to make the code more modular and easier to read and maintain. With this knowledge, you can now write more efficient and effective QBasic programs.

You may also Read:

QBASIC program to check whether the input number is positive, negative, or neutral.