What does the "return 0;" statement signify in the main function of a C++ program?

The "return 0;" statement in the main function of a C++ program signifies successful completion of the program. When a program is executed, the main function serves as the entry point, and returning a zero value typically indicates to the operating system that the program has terminated without any errors. This is a standard convention in C++ and many other programming languages, where different return values can be used to signal different outcomes. For example, returning a non-zero value usually indicates that an error has occurred during the execution of the program. Therefore, the usage of "return 0;" is crucial for communicating the success of program execution to the system that invoked the program.