Complete the attached lab18.cpp file by implementing the functions that are called by the given main function. You are not allowed to change any code in the main function. Note: use the best function title lines. Sample Output: [[swu@venus cs111]$ ./a.out [Enter your name: Andy [Enter your age: 20 Hello Andy! 16 +93 +26 = 135 Last digit of 135 is 5 Last digit of 20 is 0 [[swu@venus cs111]$ ./a.out [Enter your name: Nina [Enter your age: -1 Hello Nina! Age can't be negative [[swu@venus cs111]$ ./a.out [Enter your name: Lisa [Enter your age: 19 Hello Lisa! 28 +43 + 86 = 157 Last digit of 157 is 7 Last digit of 19 is 9 lab 18.cpp #include #include #include using namespace std; /* Implement the functions that are called in the following main function. Note: use the best function title lines. */ int main() { } string user; int age, x, y, z; cout < < "Enter your name: cin >> user; cout < < "Enter your age: cin >> age; printHello (user); //printHello prints Hello to the input // isNegative returns true if the input is negative; otherwise, returns false if (isNegative (age)) { cout < < "Age can't be negative" < < endl; exit(0); } srand(time (0)); x = twoDigitNum(); // twoDigitNum returns a random 2-digit positive integer y twoDigitNum(); z twoDigitNum(); int sum add3(x, y, z); // add3 returns the total of 3 input numbers cout < < x