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How to Determine If an Element Exists in a C Array?

Mary-Kate Olsen
Mary-Kate OlsenOriginal
2024-11-10 00:03:03344browse

How to Determine If an Element Exists in a C   Array?

Determining Element Presence in an Array (C )

Problem:
How to ascertain if an element exists within a C array?

Solution:

In Java, the equals method can be used to compare objects for equality. However, C does not support such a method for objects. Instead, the std::find function can be employed to search for a specific element:

Foo array[10];
... // Initialize the array

// std::find returns an iterator pointing to the found element or the end of the range
Foo* foo = std::find(std::begin(array), std::end(array), someObject);

if (foo != std::end(array)) {
    // Element found
    std::cerr << "Found at position " << std::distance(array, foo) << std::endl;
} else {
    // Element not found
    std::cerr << "Not found" << std::endl;
}

Explanation:

  • std::begin and std::end provide iterators to the beginning and end of the array.
  • std::find iterates through the array, comparing each element with someObject using the operator== method.
  • If the element is found, std::find returns an iterator pointing to it, and the program prints the position of the found element.
  • If the element is not found, std::find returns an iterator pointing to the end of the array, which is not equal to the iterator returned by std::begin (the beginning of the array). In this case, the program prints "Not found."

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