c-resources/CPlusPlus20ForProgrammers-m.../examples/ch06/fig06_03.cpp

51 lines
2.1 KiB
C++

// fig06_03.cpp
// Using range-based for.
#include <format>
#include <iostream>
#include <array>
int main() {
std::array items{1, 2, 3, 4, 5}; // type inferred as array<int, 5>
// display items before modification
std::cout << "items before modification: ";
for (const int& item : items) { // item is a reference to a const int
std::cout << std::format("{} ", item);
}
// multiply the elements of items by 2
for (int& item : items) { // item is a reference to an int
item *= 2;
}
// display items after modification
std::cout << "\nitems after modification: ";
for (const int& item : items) {
std::cout << std::format("{} ", item);
}
// sum elements of items using range-based for with initialization
std::cout << "\n\ncalculating a running total of items' values:\n";
for (int runningTotal{0}; const int& item : items) {
runningTotal += item;
std::cout << std::format("item: {}; running total: {}\n",
item, runningTotal);
}
}
/**************************************************************************
* (C) Copyright 1992-2022 by Deitel & Associates, Inc. and *
* Pearson Education, Inc. All Rights Reserved. *
* *
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* to determine their effectiveness. The authors and publisher make *
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**************************************************************************/