The difference between return 0; and return; in C++

The return statement has two forms:
1.return;//Return statement without return value

2.return 0;//Return statement with return value, or return a variable or a function.

The return statement without a return value is used to interrupt the execution of a function whose return value is of type void, while the return statement with a return value does not.

Code that uses return expression; fails to compile. The following is the failure code:

#include <iostream>  
using namespace std;  
  
void func(){  
    cout<<"begin"<<endl;  
    return 0;/*There is a problem here. At this time, the function of return; is equivalent to the function of break; used to interrupt the loop. So it shouldn't return a specific value. */
   cout<<"end"<<endl;  
}  
  
int main(){  
    func();  
return 0;  
}

After replacing return 0; with return;, the operation is successful:

#include <iostream>  
using namespace std;  
  
void func(){  
    cout<<"begin"<<endl;  
    return;  
    cout<<"end"<<endl;  
}  
  
int main(){  
    func();  
return 0;  
}  

Summary: The role of return; is equivalent to the role of break; used to interrupt the loop, while return 0; is another usage of return, dedicated to returning its value from a function whose return value is not void.

An extension of return:

#include <iostream>  
using namespace std;  

void func(){ //This function has no return value, so this function should use return.
    cout<<"begin"<<endl;   
    cout<<"end"<<endl;
    return;//Return the return value of the function whose return value is void, which can be executed successfully
}  
  
int main(){ //③The main function has a return value, and the return value type is int, so it can return 0
    func();  
return 0;  

}  

Compiled.