Write a program that asks the user to enter the size of a triangle to write to a
text file (an integer from 1 to 50), then print the triangle into a file by
printing a series of lines consisting of asterisks. Print “Triangle saved to
file” to the screen, but do NOT print the triangle itself to the screen, only to
the file. Name the output file triangle.txt
__Input Validation:__ If the user enters an integer less than 1 or more than 50
tell them it is out of range and have them re-enter it (do not print the
triangle for the invalid input, only for the final value in the range of 1-50
inclusive: 1 and 50 are both ok).
The first line will have one asterisk, the next two, and so on, with each line
having one more asterisk than the previous line, up to the number entered by the
user. On the next line print one less asterisk and continue by decreasing the
number of asterisks by 1 for each successive line until only one asterisk is
printed. Hint: Use nested for loops; the outside loop controls the number of
lines to print, and the inside loop controls the number of asterisks to print on
a line.
