The functions defined by 1 and void have no return values, and the functions defined by int return integer values.

2.void, which literally means "untyped", is often used to declare the parameter type, return value and pointer type of a function in programming, and has the function of commenting and limiting the program.

Extended data:

A function may or may not return a value.

1. Function without return value: The function only completes one operation, the return value type should be defined as void, and there is no return statement in the function body.

2. Function with return value: There will be a return value at the end of the function, which can be used to obtain the execution result of the function and return it to the function for external call.