Search Algorithms in C

C/BinarySearch.c

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+/*  Binary Search Algorithm : 
+        (i) Binary search is more efficient but works only on sorted arrays.
+        (ii) It divides the array in half and eliminates half of the remaining elements with each comparison.
+
+        Problem Statement : To check if number is present in the array or not using binary search
+        Test Case : 10, 23, 45, 70, 75, 80
+        Target : 70
+        Output : Element found at index 3
+*/
+
+
+#include <stdio.h>
+
+// This is binary serach algorithm's main logic 
+int binarySearch(int arr[], int size, int key) {
+    int low = 0, high = size - 1;
+
+    while (low <= high) {
+        int mid = low + (high - low) / 2; // FInd the middle of the array
+
+        if (arr[mid] == key) { // Check if middle is equal to target
+            return mid;
+        } else if (arr[mid] < key) { // Check if middle is less than target
+            low = mid + 1;
+        } else { // if middle is greater than target
+            high = mid - 1;
+        }
+    }
+    return -1;
+}
+
+int main() {
+    int arr[] = {10, 23, 45, 70, 75, 80};
+    int size = sizeof(arr) / sizeof(arr[0]);
+    int key = 70;
+
+    int result = binarySearch(arr, size, key);
+    if (result == -1) {
+        printf("Element not found\n");
+    } else {
+        printf("Element found at index %d\n", result);
+    }
+
+    return 0;
+}

C/LinearSearch.c

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+/*  Linear Search Algorithm : 
+        (i) This is the simplest searching algorithm.
+        (ii) It checks each element of the array until the desired element is found. 
+
+        Problem Statement : To check if number is present in the array or not using linear search
+        Test Case : 81, 23, 45, 30, 70, 11, 15
+        Target : 70
+        Output : Element found at index 4
+*/
+
+#include <stdio.h>
+
+// This is linear serach algorithm's main logic
+int linearSearch(int arr[], int size, int key) {
+    for (int i = 0; i < size; i++) {
+        if (arr[i] == key) {
+            return i;
+        }
+    }
+    return -1;
+}
+
+int main() {
+    int arr[] = {81, 23, 45, 30, 70, 11, 15};
+    int size = sizeof(arr) / sizeof(arr[0]);
+    int key = 70;
+
+    int result = linearSearch(arr, size, key);
+    if (result == -1) {
+        printf("Element not found\n");
+    } else {
+        printf("Element found at index %d\n", result);
+    }
+
+    return 0;
+}