How to get the Index of Specified Element in a List in C++ - Step by Step Examples

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How to get the Index of Specified Element in a List in C++ ?

Answer

To find the index of a specified element in a list in C++, you can use the std::find algorithm from the header.

✐ Examples

1 Find Index of Element in List (Integer)

In this example,

We create a list named myList with some elements.
We use the std::find algorithm to search for the specified element in the list.
If the element is found, std::find returns an iterator pointing to the first occurrence of the element. We then calculate the index using std::distance.
If the element is not found, std::find returns the end iterator of the list.
Finally, we print the index to standard output.

C++ Program

#include <iostream>
#include <list>
#include <algorithm>

int main() {
    std::list<int> myList = {10, 20, 30, 40, 50};
    int searchElement = 40;
    auto it = std::find(myList.begin(), myList.end(), searchElement);
    if (it != myList.end()) {
        int index = std::distance(myList.begin(), it);
        std::cout << "Index of element is: " << index << std::endl;
    } else {
        std::cout << "Element not found" << std::endl;
    }
    return 0;
}

Output

Index of element is: 3

2 Find Index of Element in List (String)

In this example,

We create a list named myList with some string elements.
We use the std::find algorithm to search for the specified string in the list.
If the string is found, std::find returns an iterator pointing to the first occurrence of the string. We then calculate the index using std::distance.
If the string is not found, std::find returns the end iterator of the list.
Finally, we print the index to standard output.

C++ Program

#include <iostream>
#include <list>
#include <algorithm>
#include <string>

int main() {
    std::list<std::string> myList = {"apple", "banana", "cherry", "date", "elderberry"};
    std::string searchElement = "cherry";
    auto it = std::find(myList.begin(), myList.end(), searchElement);
    if (it != myList.end()) {
        int index = std::distance(myList.begin(), it);
        std::cout << "Index of element is: " << index << std::endl;
    } else {
        std::cout << "Element not found" << std::endl;
    }
    return 0;
}

Output

Index of element is: 2

Summary

In this tutorial, we learned How to get the Index of Specified Element in a List in C++ language with well detailed examples.

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How to get the Index of Specified Element in a List in C++ - Step by Step Examples

How to get the Index of Specified Element in a List in C++ ?

Answer

✐ Examples

1 Find Index of Element in List (Integer)

C++ Program

Output

2 Find Index of Element in List (String)

C++ Program

Output

Summary

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