hope everyone's fine today. Could someone please write code on this problem so i can understand how to do problems like these? would be very grateful.

Geometry Calculator:
* Use nested if-else statements for all decision making in the program.
* Declare PI as a double constant with value 3.14159
* Use a while loop to repeat until the user types a 4 as shown below. If the operation code is not 1 through 4, then print an error message and go to the next data item.
* If a negative data value is entered by the user (or read from file), make it positive and use it.
* Use double for all your data variables and print all values with 4 decimal places.
* When the operation is 4, print "Thank you for using my calculator" and end the program.
* In the data given, the first figure is the operation value. An operation value of 1 refers a circle and the next value is the radius. An operation value of 2 refers to a rectangle and the next 2 values are the length and width. An operation value of 3 refers to a triangle and the values after it are the base and height of the triangle. Operation values of 5 and 7 should show error messages
*Any value less than 0 should be multiplied by -1 before being used.

int operation;
// display the menu
cin >> operation;
while (operation != 4)
// put your calculations here
// display the menu
cin >> operation;


1 4.58
2 6.34 5.8
3 7 -13
2 -6 19.4443
3 81.8 0.543
1 -8976
2 12.58 3

After you have the program running on the screen, change the I/O to file I/O. Your output should be as shown in the sample below, with a blank line between each output:

The area of a circle with radius 4.5800 is 14.3885
Error: 5 is not a valid operation
The area of a triangle with base 7.0000 and height 13.0000 is 45.5000
Thank you for using my calculator