65 lines
2.2 KiB
C++
65 lines
2.2 KiB
C++
// fig07_10.cpp
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// Sizeof operator when used on a built-in array's name
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// returns the number of bytes in the built-in array.
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#include <iostream>
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#include <span>
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size_t getSize(double* ptr); // prototype
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size_t getSize_span(std::span<double> ptr);
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void print_arr(auto a){
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for (auto x: a)
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std::cout << x << " ";
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}
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void fill_arr(auto& a){
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for (auto x: a)
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x = 0;
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}
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int main() {
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double numbers[20]; // 20 doubles; occupies 160 bytes on our system
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auto numbers_span {std::span<double>(numbers)};
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fill_arr(numbers_span);
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std::cout << "Number of bytes in numbers is " << sizeof(numbers)<<"\n";
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std::cout << "Actual number of elements : " << sizeof(numbers)/sizeof(double) << "\n";
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std::cout << "Number of bytes returned by getSize is " << getSize(numbers) << "\n";
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std::cout << "Actual number of elements returned by getSize_span is " << getSize_span(numbers) << "\n";
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print_arr(numbers_span);
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}
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// return size of ptr
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size_t getSize(double* ptr) {
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return sizeof(ptr);
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}
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size_t getSize_span(std::span<double> ptr) {
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return ptr.size();
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}
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/**************************************************************************
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* (C) Copyright 1992-2022 by Deitel & Associates, Inc. and *
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* Pearson Education, Inc. All Rights Reserved. *
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* *
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* DISCLAIMER: The authors and publisher of this book have used their *
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* best efforts in preparing the book. These efforts include the *
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* development, research, and testing of the theories and programs *
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* to determine their effectiveness. The authors and publisher make *
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* no warranty of any kind, expressed or implied, with regard to these *
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* programs or to the documentation contained in these books. The authors *
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* and publisher shall not be liable in any event for incidental or *
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* consequential damages in connection with, or arising out of, the *
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* furnishing, performance, or use of these programs. *
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**************************************************************************/
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