use c99 to solve

Write a program that askes the user to enter a password. the password should not contain spaces. After your program reads the password from keyboard, it will call a special function named encrypt(char[]) which encrypts the password according to the following rules: (assume the password is small letters) 1. reverse the word. 2. if it contains the character 's' then replace it with $ 3. if it contains the character 'a' then replace it with@ 4. if it contains the character 'o' then replace it with 'O' (zero) The encrypted password should be stored in a file named login.txt