C++ Programming - 2nd Study

C++ Programming - 2nd Study

• 3.
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• 4.
  #include <iostream> int main() { intarr[] = { 1, 2, 3, 4, 5 }; for (int i = 0; i < 5; ++i) std::cout << arr[i] << std::endl; return 0; } #include <iostream> int main() { int arr[] = { 1, 2, 3, 4, 5 }; for (auto& i : arr) std::cout << i << std::endl; return 0; } C / C++98 C++11 4
• 5.
  def mean(seq): n =0.0 for x in seq: n += x return n / len(seq) auto mean(const Sequence& seq) { auto n = 0.0; for (auto& x : seq) n += x; return n / seq.size(); } Python C++11 5
• 7.
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• 8.
  int main() { int i; int**arr = (int**)malloc(sizeof(int*) * 5); for (i = 0; i < 5; ++i) arr[i] = (int*)malloc(sizeof(int) * 5); // ... for (i = 0; i < 5; ++i) free(arr[i]); free(arr); arr = NULL; return 0; } C 8
• 9.
  int main() { int** arr= new int*[5]; for (int i = 0; i < 5; ++i) arr[i] = new int[5]; // ... for (int i = 0; i < 5; ++i) delete[] arr[i]; delete[] arr; arr = NULL; return 0; } C++ 9
• 10.
  #include <iostream> int main() { int*p1 = new int; delete p1; p1 = NULL; int* p2 = new int[10]; delete[] p2; p2 = NULL; return 0; } C++ 10
• 12.
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• 13.
  #include <iostream> void f(inta) { std::cout << "f(int)" << std::endl; } void f(int* p) { std::cout << "f(int*)" << std::endl; } int main() { f(0); f(NULL); return 0; } C / C++98 13
• 14.
  #include <iostream> void f(inta) { std::cout << "f(int)" << std::endl; } void f(int* p) { std::cout << "f(int*)" << std::endl; } int main() { f(nullptr); return 0; } C++11 14
• 15.
  #include <iostream> int main() { std::cout<< sizeof(nullptr) << std::endl; std::cout << typeid(nullptr) .name() << std::endl; return 0; } C++11 15
• 16.
  C++98 #include <iostream> int main() { int*p1 = new int; delete p1; p1 = NULL; int* p2 = new int[10]; delete[] p2; p2 = NULL; return 0; } C++11 #include <iostream> int main() { int* p1 = new int; delete p1; p1 = nullptr; int* p2 = new int[10]; delete[] p2; p2 = nullptr; return 0; } 16
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• 19.
  http://en.cppreference.com/w/cpp/language/static_cast http://en.cppreference.com/w/cpp/language/dynamic_cast http://en.cppreference.com/w/cpp/language/const_cast http://en.cppreference.com/w/cpp/language/reinterpret_cast 19
• 20.
  C #include <iostream> int main() { char*str = "Hello, World"; int* pi = (int*)str; char* pc = (char*)*pi; std::cout << pc << std::endl; return 0; } 20
• 21.
  C++ #include <iostream> int main() { char*str = "Hello, World"; int* pi1 = static_cast<int*>(str); char* pc1 = static_cast<char*>(*pi1); std::cout << pc1 << std::endl; return 0; } 21