C++ 编程/作用域/示例/混淆范围程序

// Confusing Scope Program
#include <iostream>

using namespace std;

int i = 5;           /* The first version of the variable 'i' is now in scope */

void p(){
  int i = -1;        /* A ''new'' variable, also called 'i' has come into existence. The 'i' declared above is now out of scope,*/
  i = i + 1;
  cout << i << ' ';  /* so this ''local'' 'i' will print out the value 0.*/
}                    /* The newest variable 'i' is now out of scope. The first variable, also called 'i', is in scope again now.*/

int main(){
  cout << i << ' ';  /* The first variable 'i' is still in scope here so a ''5'' will be output here.*/
  char ch;
  int i = 6;         /* A ''new'' variable, also called 'i' has come into existence. The first variable 'i' is now out of scope again,*/
  i = i + 1;
  p();
  cout << i << endl; /* so this line will print out a ''7''.*/
  return 0;
}                    /* End of program: all variables are, of course, now out of scope.*/