Need help for Java code for Below question:

4.1: Roman Numeral Converter

Write a program that asks the user to enter a number within the range of 1 through 10. Use a switch statement to display the Roman numeral version of that number.

Input Validation: Do not accept a number less than 1 or greater than 10.

Prompts And Output Labels. Use the following prompt for input: "Enter a number in the range of 1 - 10: ". The output of the program should be just a Roman numeral, such as VII.

CLASS NAMES. Your program class should be called RomanNumerals

3.12: The Speed of Sound

The speed of sound depends on the material the sound is passing through. Below is the approximate speed of sound (in feet per second) for air, water and steel:

air: 1,100 feet per second

water: 4,900 feet per second

steel: 16,400 feet per second

Write a program class TheSpeedOfSound that asks the user to enter "air", "water", or "steel", and the distance that a sound wave will travel in the medium. The program should then display the amount of time it will take.

You can calculate the amount of time it takes sound to travel in air with the following formula: time = distance/1,100

You can calculate the amount of time it takes sound to travel in watert with the following formula: time = distance/4,900

You can calculate the amount of time it takes sound to travel in steel with the following formula: time = distance/16,400

Prompts And Output. The program prompts for the medium with: "Enter one of the following: air, water, or steel: " and reads the medium. If the medium is not air, water or steel the program prints the message: "Sorry, you must enter air, water, or steel." an nothing else. Otherwise the program prompts for the distance with ("Enter the distance the sound wave will travel: " and reads it in and then prints "It will take x seconds." where x is the time calculated by your program.

21020. Assume the input data is structured as follows: first there is a non-negative integer specifying the number of employee timesheets to be read in. This is followed by data for each of the employees. The first number for each employee is an integer that specifies their pay per hour in cents. Following this are 5 integers, the number of hours they worked on each of the days of the workweek. Given this data, and given that an intvariable total has been declared, write a loop and any necessary code that reads the data and stores the total payroll of all employees in total. Note that you will have to add up the numbers worked by each employee and multiply that by that particular employee's pay rate to get the employee's pay for the week-- and sum those values into total.

ASSUME the availability of a variable, stdin, that references a Scanner object associated with standard input.

4.9: Population

Write a program that will predict the size of a population of organisms. The program should ask the user for the starting number of organisms, their average daily population increase (as a percentage, expressed as a fraction in decimal form: for example 0.052 would mean a 5.2% increaseeach day), and the number of days they will multiply. A loop should display the size of the population for each day.

Prompts, Output Labels and Messages.The three input data should be prompted for with the following prompts: "Enter the starting number organisms: ", "Enter the daily increase: ", and "Enter the number of days the organisms will multiply: " respectively. After the input has been read in successfully, a table is produced, for example:

-----------------------------

2 300.0

4 675.0

Under the heading is a line of 29 dashes followed by one line for each day, showing the day number and the population at the beginning of that day.

Input Validation.Do not accept a number less than 2 for the starting size of the population. If the user fails to satisfy this print a line with this message "Invalid. Must be at least 2. Re-enter: " and try to read the value. Similarly, do not accept a negative number for average daily population increase, using the message "Invalid. Enter a non-negative number: " and retrying. Finally, do not accept a number less than 1 for the number of days they will multiply and use the message "Invalid. Enter 1 or more: ".

19. Squares. Write a program class named SquareDisplay that asks the user for a positive integer no greater than 15. The program should then display a square on the screen using the character 'X'. The number entered by the user will be the length of each side of the square. For example, if the user enters 5, the program should display the following:

XXXXX

XXXXX

XXXXX

XXXXX

XXXXX

INPUT and PROMPTS. The program prompts for an integer as follows: "Enter an integer in the range of 1-15: ".

OUTPUT. The output should be a square of X characters as described above.

CLASS NAMES. Your program class should be called SquareDisplay