int main()
 

why use "int main()" when you can use "void main()"?

it's always good to return an exit code from a program. the value you reply can infer wether the program executed correctly. nearly all programs return exit codes. for example...

[chris@trevor chris]$ ls hello
ls: hello: No such file or directory
[chris@trevor chris]$ echo $?
1
[chris@trevor chris]$ touch hello
[chris@trevor chris]$ ls hello
hello
[chris@trevor chris]$ echo $?
0
[chris@trevor chris]$

so from this we can tell if ls was successful or not.