Linear Search in C++

Example 1: Linear Search in a Static Integer Array (Iterative Method)

This example demonstrates how to implement linear search using a simple for loop. The array is predefined (static), and we look for a specific integer value by comparing each element one by one.

Code:

#include <iostream>
using namespace std;

int main() {
int arr[] = {4, 15, 7, 23, 11};
int n = sizeof(arr) / sizeof(arr[0]);
int key = 23;
bool found = false;

for (int i = 0; i < n; i++) {
if (arr[i] == key) {
cout << "Element found at index " << i << endl;
found = true;
break;
}
}

if (!found)
cout << "Element not found" << endl;

return 0;
}

Output:

Element found at index 3

Explanation:

• We search for 23 in a hard-coded array using a loop.
• Once found, it prints the index and exits early.

Example 2: Linear Search in a Vector of Strings (Using std::find)

In this example, we use the Standard Template Library (STL) function std::find to search for a string in a vector. This method simplifies the code and works well with C++ containers like vectors.

Code:

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
vector<string> fruits = {"apple", "banana", "mango", "grape", "kiwi"};
string key = "mango";

auto it = find(fruits.begin(), fruits.end(), key);

if (it != fruits.end()) {
cout << "Fruit found at index " << (it - fruits.begin()) << endl;
} else {
cout << "Fruit not found" << endl;
}

return 0;
}

Output:

Fruit found at index 2

Explanation:

• Searches for “mango” in a vector of strings using std::find.
• It prints the index if found.