Question

In ASCII, the upper letter 'A' is a 65, 'B' is a 66, 'C' is a 67. The remaining uppercase letters follows. Write the code in C++ to ask for an uppercase letter. Validate that the letter is uppercase. If the letter is not uppercase, print an appropriate message. Do not let the execution of the continue until an uppercase letter has been entered.

Answer 1

The student's question requires writing a C++ program that prompts for and validates an uppercase letter, using a loop and the isupper() function. The code loops, asking for input until an uppercase letter is entered.

Step-by-step explanation:

The ASCII values for uppercase letters in C++ start with 65 for 'A' and continue sequentially. To write code in C++ that asks for an uppercase letter and validates it, you can use a while loop and the isupper() function from the cctype library.

Here is an example of such a program:

#include
#include // for isupper() function

int main() {
char letter;
std::cout << "Enter an uppercase letter:";
std::cin >> letter;

while (!isupper(letter)) {
std::cout << "Invalid input. Please enter an uppercase letter:";
std::cin >> letter;
}

std::cout << "You entered an uppercase letter: " << letter << '\\';
return 0;
}

This code repeatedly asks the user to input a letter until they enter an uppercase one. The isupper() function checks if the given character is an uppercase letter. If it is not, the program prints an error message and requests a new letter, looping until a valid uppercase letter is provided.