create a QBASIC program using DO WHILE LOOP
Sure! I can help you create a QBASIC program using a DO WHILE loop.
The DO WHILE loop in QBASIC allows you to execute a block of code repeatedly as long as a condition is true. Here's an example program that uses a DO WHILE loop to calculate the sum of numbers entered by the user until they enter a negative number:
```
CLS
sum = 0
DO
PRINT "Enter a number:"
INPUT num
IF num >= 0 THEN
sum = sum + num
END IF
LOOP WHILE num >= 0
PRINT "The sum of the numbers entered is: "; sum
END
```
Explanation:
1. The `CLS` command clears the screen.
2. The variable `sum` is initialized to 0. This variable will store the sum of the numbers entered by the user.
3. The DO WHILE loop starts with the keyword `DO` and ends with the keyword `LOOP WHILE`. The code block between these keywords will be executed repeatedly as long as the condition `num >= 0` is true.
4. Inside the loop, the program prompts the user to enter a number using the `PRINT` statement and retrieves the user input using the `INPUT` statement.
5. The IF statement checks if the number entered is greater than or equal to 0. If it is, the number is added to the `sum` variable using the `sum = sum + num` expression.
6. The loop continues until the user enters a negative number, at which point the condition `num >= 0` becomes false, and the loop terminates.
7. After the loop, the program prints the final sum using the `PRINT` statement.
8. Finally, the program ends with the `END` statement.
That's it! You can run the program by saving it with a .BAS extension and executing the QBASIC interpreter or IDE.