Grade-10 Ch-8 Review of Qbasic program lab work RoseBud

 Here are some lab work questions related to QBasic using control flow structures such as IF, IF...ELSE, IF...ELSEIF...ELSE, and SELECT CASE statements, along with answers and explanations:

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Lab Work Questions and Answers in QBasic

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Question 1: Using the IF statement

Write a program to check if a number entered by the user is positive, negative, or zero using the IF statement.

Answer:

CLS
INPUT "Enter a number: ", N

IF N > 0 THEN
    PRINT "The number is positive."
ELSEIF N < 0 THEN
    PRINT "The number is negative."
ELSE
    PRINT "The number is zero."
END IF
END

Explanation:

• This program uses a simple IF statement to check if a number is greater than zero (positive), less than zero (negative), or equal to zero. Based on the condition, it prints the respective message.

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Question 2: Using the IF...ELSE statement

Write a program to check whether a student has passed or failed based on their marks. Assume the passing marks are 50. If the marks are greater than or equal to 50, the student passes; otherwise, they fail.

Answer:

CLS
INPUT "Enter the student's marks: ", marks

IF marks >= 50 THEN
    PRINT "The student has passed."
ELSE
    PRINT "The student has failed."
END IF
END

Explanation:

• The IF...ELSE statement checks if the student's marks are greater than or equal to 50. If true, it prints "The student has passed"; otherwise, it prints "The student has failed."

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Question 3: Using the IF...ELSEIF...ELSE statement

Write a program that checks the grade of a student based on their marks:

• 80 and above: "A"
• 60 to 79: "B"
• 40 to 59: "C"
• Below 40: "Fail"

Answer:

CLS
INPUT "Enter the student's marks: ", marks

IF marks >= 80 THEN
    PRINT "Grade: A"
ELSEIF marks >= 60 THEN
    PRINT "Grade: B"
ELSEIF marks >= 40 THEN
    PRINT "Grade: C"
ELSE
    PRINT "Fail"
END IF
END

Explanation:

• The IF...ELSEIF...ELSE statement is used to check multiple conditions and print the grade according to the marks entered by the student.

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Question 4: Using the SELECT CASE statement

Write a program that takes an integer input (1 to 7) from the user and prints the corresponding day of the week (1 = Sunday, 2 = Monday, ..., 7 = Saturday).

Answer:

CLS
INPUT "Enter a number (1-7): ", day

SELECT CASE day
    CASE 1
        PRINT "Sunday"
    CASE 2
        PRINT "Monday"
    CASE 3
        PRINT "Tuesday"
    CASE 4
        PRINT "Wednesday"
    CASE 5
        PRINT "Thursday"
    CASE 6
        PRINT "Friday"
    CASE 7
        PRINT "Saturday"
    CASE ELSE
        PRINT "Invalid input! Please enter a number between 1 and 7."
END SELECT
END

Explanation:

• The SELECT CASE statement is used here to check the number entered by the user and display the corresponding day of the week. If the number is not between 1 and 7, it prints "Invalid input."

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Question 5: Using the IF statement with logical operators

Write a program that checks if a given number is within a specific range (for example, between 10 and 20 inclusive).

Answer:

CLS
INPUT "Enter a number: ", N

IF N >= 10 AND N <= 20 THEN
    PRINT "The number is between 10 and 20."
ELSE
    PRINT "The number is outside the range."
END IF
END

Explanation:

• The IF statement uses the logical operator AND to check if the number is between 10 and 20, inclusive. If true, it prints the corresponding message.

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Question 6: Using the SELECT CASE statement for multiple conditions

Write a program to enter a month number (1 to 12) and print the number of days in that month. Assume February has 28 days (not accounting for leap years).

Answer:

CLS
INPUT "Enter the month number (1-12): ", month

SELECT CASE month
    CASE 1, 3, 5, 7, 8, 10, 12
        PRINT "31 days"
    CASE 4, 6, 9, 11
        PRINT "30 days"
    CASE 2
        PRINT "28 days"
    CASE ELSE
        PRINT "Invalid month number!"
END SELECT
END

Explanation:

• The SELECT CASE statement is used to check which month is entered and print the number of days in that month. It covers months with 31 days, 30 days, and February (28 days).

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Summary of Control Flow Statements Used

1. IF Statement:

   • Used to check a single condition and execute a block of code if the condition is true.

2. IF...ELSE Statement:

   • Used to check a condition and execute one block of code if true, and another block if false.

3. IF...ELSEIF...ELSE Statement:

   • Used to check multiple conditions in sequence and execute the corresponding block of code for the first true condition.

4. SELECT CASE Statement:

   • Used to check a variable against several possible values and execute the corresponding block of code based on the value.

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These lab work questions help practice decision-making structures in QBasic, allowing for a deeper understanding of control flow in programming.