Use the input.txt file. Have it read in the number of records to work on. Then for each record read in a character. If it is a C then read in a value and calculate and display the area of a circle (pi*r2), a R then read in two values and calculate and display the area of a rectangle (length * width), and if it is a T then read in two values and calculate and display the area of a triangle (1/2 * base * height).
Data file to test with:
5
C 13
R 7 9
C 5
T 12 10
R 23 8