Have you ever organized a contest. Sometimes it happens that while checking questions for the contest we prefer not to use the software like the pc2 or any contest s/w. Then the major problem is compiling. You cannot compile a file by typing its name line by line and doing the funny stuff around that. So here it is: use batch. All you have to do is copy the code to a file and rename it as something. batch. Drag and drop to see the output and you'll find your life easier:

a.in is the file containing the input. a.out contains the output.
Code: G++

del a.out
g++ %1 -o a.exe
a.exe,a.out
notepad a.out

del a.out
gcc -lm %1 -o a.exe
a.exea.out
notepad a.out