Answer to Question #43660 in C++ for C+ help i'm lost? Scope of Variable Names

Question

C++ Investigate the operation of scope rules in a program.


// VariableNameScope

#include <iostream>

using namespace std;

int i = 111;

int main()
{
{
int i = 222;
{
int i = 333;
cout << "i = " << i << endl;
{
int i = 444;
cout << "i = " << i << endl;
{
cout << "i = " << i << endl;
}
}
}

cout << "i = " << i << endl;
}

cout << "i = " << i << endl;

return 0;
}


Q1: What are the scope rules you observed in the program?

i want to say Global scope(int i = 111;),Local scope (int i = 333;), and function scope (int i = 222;) but now, i'm confused. I really don't understand what is this question asking me. Can somebody help me break it down

Answer 1

Each block creates its own scope. 
Variables created before the block will be visible and can be used in all nested blocks. 
If you create a variable inside 
a block with the same name as the outside will be used only one that has been defined inside!
Exaple 
int main ()
{
      int x = 5;   // Create outside variable ,this variable can be used in all nested blocks!
   cout<<"X = "<<x<<endl;//X = 5
   {
      cout<<"X = "<<x<<endl;//On display you can see 5 , because variable x not redefine  
      int x = 3;//redefine variable ,now this variable can be used in all nested blocks!
      cout<<"X = "<<x<<endl;//X = 3
      {
         cout<<"X = "<<x<<endl;//On display you can see 3 , because variable x not redefine  
         int x = 0;//redefine variable ,now this variable can be used in all nested blocks!
         cout<<"X = "<<x<<endl;//X = 0
      }
      //when end of block; variable x saved outside value 
      cout<<"X = "<<x<<endl;//X = 3
   }
   //when end of block; variable x saved outside value 
   cout<<"X = "<<x<<endl;//X = 3
   return 0;
}
in your example :
#include <iostream>
using namespace std;
int i = 111;// define global variable 
int main()
{
   { // create block - 1
      int i = 222;//redefine variable i and now this variable can be used in all nested blocks! 
      {// create block - 2 
         int i = 333;//redefine variable i and now this variable can be used in all nested blocks! 
         cout << "i = " << i << endl;//print redefine(in block - 2 )  variable 
         {// create block - 3
 
            int i = 444;//redefine variable i and now this variable can be used in all nested blocks!
            cout << "i = " << i << endl;//print redefine(in block - 3 )  variable 
            {
               cout << "i = " << i << endl;//print define(in block - 3 )  variable 
            }
         }
      }
      cout << "i = " << i << endl;//print define(in block - 1 )  variable 
   }
   cout << "i = " << i << endl;//print  global define  variable 
}