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  1. #include <iostream>
  2. #include <vector>
  3.  
  4. struct item
  5. {
  6.     int numItems = 0;
  7.     float price = 0;
  8.     double foo = 0;
  9.  
  10.     item(int num, float pr, double f)
  11.     {
  12.         numItems = num;
  13.         price = pr;
  14.         foo = f;
  15.     }
  16. };
  17.  
  18. template <class T>
  19. void printValues(item* vecItemPtr, T* targetElemPtr, int numItems)
  20. {
  21.     ptrdiff_t targetElementOffset = reinterpret_cast<char*>(targetElemPtr) - reinterpret_cast<char*>(vecItemPtr);
  22.  
  23.     for (int i = 0; i < numItems; i++)
  24.     {
  25.         std::cout << *reinterpret_cast<T*>(reinterpret_cast<char*>(vecItemPtr + i) + targetElementOffset) << std::endl;
  26.     }
  27. }
  28.  
  29. int main()
  30. {
  31.     std::vector<item> test;
  32.  
  33.     item item1(10, 3.0f, 8);
  34.     item item2(20, 1.0f, 4);
  35.  
  36.     test.reserve(2);
  37.     test.push_back(item1);
  38.     test.push_back(item2);
  39.  
  40.     // Say I want to print numItems, 
  41.     printValues(&test[0], &test[0].numItems, test.size());
  42.  
  43.     // Say I want to print price
  44.     printValues(&test[0], &test[0].price, test.size());
  45.  
  46.     // Say I want to print foo
  47.     printValues(&test[0], &test[0].foo, test.size());
  48. }
Success #stdin #stdout 0.01s 5452KB
comments ()
stdin
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Standard input is empty
stdout
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10
20
3
1
8
4
https://ideone.com/4oCbzx
language:
C++ 4.3.2 (gcc-4.3.2)
created:
3 years ago
visibility:
public

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