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 }