Line 10
return 0; // indicate that program ended successfully
is one of several means we’ll use to exit a function. When the return statement is used at the end of main
, as shown here, the value 0
indicates that the program has terminated successfully. The right brace, }
, (line 11) indicates the end of function main
. According to the C++ standard, if program execution reaches the end of main
without encountering a return
statement, it’s assumed that the program terminated successfully—exactly as when the last statement in main is a return
statement with the value 0
. For that reason, we omit the return
statement at the end of main
in subsequent programs.