Main function
From cppreference.com
                    
                                        
                    
                    
                                                            
                    A program shall contain a global function called main, which is the designated start of the program.
 int main () { body } 
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 int main (int argc, char *argv[]) { body } 
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[edit] Explanation
| argc | - | the number of arguments passed to the program from the environment in which the program is run. | 
| argv | - | These arguments are passed as null-terminated multibyte strings in argv[0] through argv[argc-1], the value of argv[argc] is 0. | 
| body | - | the body of the main function. As a special case, if control reaches the end of main without encountering a return statement, the effect is that of executing return 0; |