Simple C++ input from file…how to?

Question

I have a file:

P 0.5 0.6 0.3
30 300
80 150
160 400
200 150
250 300
T
r  45 0 0
s 0.5 1.5 0 0
t 200 –150
.
.
.

When I read in \'P\' I know that

Answer 1

• Keep a kind of 'global state'
• Write a loop that reads a line from the file until end-of-file.
• Read the line into a buffer
• Check the first character of the buffer, if it is P or T or r or s or t, change the global state of the application
• If the first character was a T, use a sscanf(Buffer+1,"%lf %lf %lf",&first,&second,&third) to read the rest of the line.
• Do something similar if the first character is r, s or t.
• If the application is in the 'P-state' just scan the buffer using sscanf(Buffer,"%lf %lf",&first,&second)