How to use linear search algorithm in C++

How to use the linear search algorithm in C

Linear search is a simple and intuitive search algorithm, also known as sequential search. It starts from the first element of the data set and checks one by one until it finds the target element or traverses the entire data set. In this article, we will learn how to use the linear search algorithm in C and provide concrete code examples.

1. Algorithm principle:

The principle of the linear search algorithm is very simple. It compares the target elements one by one according to the order of the elements in the data set. The specific steps are as follows:

• Start checking from the first element;
• If the current element matches the target element, return the index of the current element;
• If the current element If the element does not match the target element, continue to check the next element;
• If the entire data set is traversed and the target element is not found, a special value (such as -1) is returned to indicate that it was not found.

2. Code example:

Here is an example code for finding using linear search algorithm:

#include <iostream>
#include <vector>

int linearSearch(const std::vector<int>& data, int target) {
    for (int i = 0; i < data.size(); i++) {
        if (data[i] == target) {
            return i; // 返回目标元素的索引
        }
    }
    return -1; // 未找到目标元素
}

int main() {
    std::vector<int> data = {10, 5, 8, 2, 7};
    int target = 8;
    int index = linearSearch(data, target);

    if (index != -1) {
        std::cout << "目标元素 " << target << " 在索引 " << index << " 处找到！" << std::endl;
    } else {
        std::cout << "未找到目标元素 " << target << "！" << std::endl;
    }

    return 0;
}

In the above example, We define a function called linearSearch that accepts a vector containing integers and the target element as arguments. We use a for loop to compare the elements in the data with the target element one by one, and return the index of the current element when found, otherwise return -1.

In the main function, we create a vector data containing integers and define the target element target as 8. We then call the linearSearch function and store the returned index in the index variable. Finally, we output the results to the console.

3. Summary:

The linear search algorithm is a simple and intuitive search algorithm suitable for small or unordered data sets. Its time complexity is O(n), where n is the size of the data set. Although it is relatively inefficient, it is a good starting point for learning and understanding search algorithms.

I hope this article can help you understand how to use the linear search algorithm in C and provides specific code examples. If you have any questions or concerns, please feel free to leave a message. Happy programming!

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