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  1. #include <iostream>
  2.  
  3. namespace A {
  4. 	namespace B {
  5. 		struct C {
  6. 			struct D {
  7.                 int e;	// variable e lifetime is same with struct D lifetime. Available only within struct D initialized
  8.                 D() : e(42) {}
  9. 			} d;	// variable d lifetime is samw with C struct lifetime. Available only within struct C initialized
  10. 			C() {}
  11. 			C(int v) {
  12. 				d.e = v;
  13. 			}
  14. 		} c;	// variable c lifetime is entire program. Scope is A::B::c
  15. 	}
  16. }
  17.  
  18. int main() {
  19. 	// access variable with program lifetime in A::B namespace
  20. 	std::cout << A::B::c.d.e << std::endl;
  21.  
  22. 	// create local variable of type A::B::C and access its fields
  23. 	A::B::C myc(55);
  24. 	std::cout << myc.d.e << std::endl;
  25.  
  26. 	// declare struct F within main function scope and access its fields
  27. 	struct F {
  28. 		int g;
  29. 		F(int v) : g(v) { }
  30. 	} f (100);
  31. 	std::cout << f.g << std::endl;
  32.  
  33. 	return 0;
  34. }
Success #stdin #stdout 0s 3456KB
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stdin
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Standard input is empty
stdout
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42
55
100
https://ideone.com/tWhGRm
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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