an assignment that i am having trouble with coding

Write a program that prompts the user to input (word/statement), Accepts only letters. The program then: 1.Remove all the vowels from the (word /statement) then output the (word /statement) without vowels. 2. Outputs the number of vowels. 3. Convert the lowercase vowels letters to uppercase and vice versa. Conditions: 1. Use only (while Or do-while loop). Do everything outside the main function except declarations.