int main( void )

Every program in C begins executing at the function main

The keyword int  indicates that main “returns” an integer value

The void  Means that main does not receive any information

The backslash (\) is called an escape character轉義字元

return 0; /* indicate that program ended successfully */

Included at the end of every main function

The keyword return is to exit a function

When the return statement is used at the end of main, the value 0 indicates that the program has terminated successfully