A scope or block scope is a visiblity and validiity construct of C and languages with similar syntax such as C++, Java, etc.

Names, e.g. variables, declared in a scope are usually only visible within the scope and nested scopes, not outside, i.e. not in the parent scope or sibling scopes.

Languages such as C and C++, which allow data on the stack, destroy such data when the variable's scope ends.

Qt Code: 
  1. int main()
  2. {
  3.   // inside scope of main()
  4.   int a;
  5.  
  6.   a = 3; // valid
  7.  
  8.   {
  9.     int b;
  10.  
  11.     // inside a nested scope
  12.     a = 4; // valid
  13.     b= 4; // valid
  14.   }
  15.  
  16.   a = 5; // valid;
  17.   b = 5; // will not compile, b only visible/valid in nested scope
  18. }
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In C++, an object such as std::vector is destroyed (its destructor is invoked) when the scope it lives in ends.
Qt Code: 
  1. int main()
  2. {
  3.   vector<int> a;
  4.  
  5.   {
  6.     vector<int> b;
  7.  
  8.   }// b is destroyed
  9.  
  10. }// a is destroyed
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Cheers,
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