You are required to design a QBASIC program that receives a student test score and prints out her grade, the grading criteria is as follows <60% is an F, 60 to 69 is a D, 70 to 70 is a C, 80 to 89 is a B, >=90 is A.
To design a QBASIC program that receives a student test score and prints out her grade according to the provided grading criteria, follow these steps:
1. Prompt the user to enter the student's test score.
2. Accept the input from the user and store it in a variable, let's say "score".
3. Based on the value of "score," determine the grade using an IF-THEN-ELSEIF-ELSE statement.
4. Print the corresponding grade based on the score using PRINT statement.
Here's the QBASIC code for the program:
```
CLS
PRINT "Enter the student's test score:"
INPUT score
IF score < 60 THEN
PRINT "Grade: F"
ELSEIF score >= 60 AND score <= 69 THEN
PRINT "Grade: D"
ELSEIF score >= 70 AND score <= 79 THEN
PRINT "Grade: C"
ELSEIF score >= 80 AND score <= 89 THEN
PRINT "Grade: B"
ELSEIF score >= 90 THEN
PRINT "Grade: A"
ELSE
PRINT "Invalid input. Please enter a valid test score."
END IF
```
Explanation:
- The `CLS` statement clears the screen before running the program.
- The `PRINT` statement prompts the user to enter the student's test score.
- The `INPUT` statement accepts the input from the user and assigns it to the variable `score`.
- The IF-THEN-ELSEIF-ELSE statement checks the value of `score` against different ranges to determine the grade.
- If the score is less than 60, it prints the grade as "F" using the `PRINT` statement.
- If the score is between 60 and 69 (inclusive), it prints the grade as "D".
- If the score is between 70 and 79 (inclusive), it prints the grade as "C".
- If the score is between 80 and 89 (inclusive), it prints the grade as "B".
- If the score is 90 or above, it prints the grade as "A".
- If the input is not within the valid score range, it prints an error message using the ELSE statement.
- The `END IF` statement signifies the end of the IF-THEN-ELSEIF-ELSE block.
- When you run the program, the grade corresponding to the input score will be displayed on the screen.