I want to write a program in C does the following

When the user runs the program, the following start menu should appear:
M- Math functions.
A- Array functions.
C- Convert functions.
X- Exit.
What's Your Choice?
Start menu tasks description:
1. If the user pressed (M), a sub menu (functions menu) should appear including at least 4 functions as follows:
1. Factorial (n).
2. Power (base, power).
3. ……….
4. ……….
5. ……….
What's Your Choice?
For example, when the user presses (1), he\she will enter a number you need to calculate its factorial and so on.
2 If the user pressed (A), a sub menu (array menu) should appear including five choices as follow:
1. Enter array elements.
2. View array elements.
3. Search about an element.
4. Sort array elements.
5. Statistic.
What's Your Choice?
.3 If the user pressed (C), a sub menu should appear including three choices as follow:
1. Convert a Capital letter into small letter.
2. Convert from Fahrenheit unit to Celsius unit.
3. Convert from Cm into Inch.
What's Your Choice?
4. If the user pressed (X), the program will exit.