Question $1($Simple Grading System$)$: $(1$ mark$)$

Write a C$++$ program that does the following:

$$ Prompts the user to enter their score for a recent exam $($a value between $0$ and $100).$

$$ Using an if$-$else statement, the program should determine the grade based on the following criteria:

o$$ Score $90$ and above: Grade A

o$$ Score $80-89$: Grade B

o$$ Score $70-79$: Grade C

o$$ Score $60-69$: Grade D

o$$ Score below $60$: Grade F

$$ After determining the grade, the program should output a message with the user's score and corresponding grade.

$$

Example:

Input:

Enter your exam score: $85$

Output:

Your score is $85,$ and your grade is B$.$

$$

$$

Question $2($Simple Calculator$)$: $(2$ marks$)$

Write a C$++$ program that does the following:

$$ Prompts the user to enter two numbers.

$$ Asks the user to choose an operation $(+,-,*,/).$

$$ Using a switch statement, the program should perform the chosen operation on the two numbers and display the result.

$$ If the user enters an invalid operation, the program should display an error message.

Example:

Input:

Enter first number: $10$

Enter second number: $5$

Choose an operation $(+,-,*,/)$: $*$

$$

Output:

Result: $10*5=50$

$$

Invalid Operation Example:

Input:

Enter first number: $10$

Enter second number: $5$

Choose an operation $(+,-,*,/)$: $\%$

$$

Output:

Error: Invalid operation.

$$

$$

$$

Question $3($Find Duplicate Value$)$: $(2$ marks$)$

Write a C$++$ program that does the following:

$$ Prompts the user to enter four integer values.

$$ The program should check if any two or more of the values are duplicates.

$$ If a duplicate is found, the program should print a message saying which value is duplicated.

$$ If no duplicates are found, the program should print a message indicating that all values are unique.

$$

Example $1$:

Input:

Enter four integers: $3735$

$$

Output:

Duplicate value found: $3$

$$

Example $2$:

Input:

Enter four integers: $1234$

$$

Output:

All values are unique.

$$