Improved linear search: return index, input validation, multpile queries

searching/linear_search.c

@@ -3,33 +3,63 @@
 
 int linearsearch(int *arr, int size, int val)
 {
-    int i;
-    for (i = 0; i < size; i++)
+    for (int i = 0; i < size; i++)
     {
         if (arr[i] == val)
-            return 1;
+            return i;  // Return index if found
     }
-    return 0;
+    return -1;  // Not found
+}
+
+void printArray(int *arr, int size)
+{
+    printf("Array contents: ");
+    for (int i = 0; i < size; i++)
+        printf("%d ", arr[i]);
+    printf("\n");
 }
 
 int main()
 {
-    int n, i, v;
+    int n;
     printf("Enter the size of the array:\n");
-    scanf("%d", &n);  // Taking input for the size of Array
+    scanf("%d", &n);
+
+    if (n <= 0)
+    {
+        printf("Invalid array size!\n");
+        return 1;
+    }
 
     int *a = (int *)malloc(n * sizeof(int));
-    printf("Enter the contents for an array of size %d:\n", n);
-    for (i = 0; i < n; i++)
-        scanf("%d", &a[i]);  // accepts the values of array elements until the
-                             // loop terminates//
-
-    printf("Enter the value to be searched:\n");
-    scanf("%d", &v);  // Taking input the value to be searched
-    if (linearsearch(a, n, v))
-        printf("Value %d is in the array.\n", v);
-    else
-        printf("Value %d is not in the array.\n", v);
+    if (a == NULL)
+    {
+        printf("Memory allocation failed!\n");
+        return 1;
+    }
+
+    printf("Enter %d elements:\n", n);
+    for (int i = 0; i < n; i++)
+        scanf("%d", &a[i]);
+
+    printArray(a, n);
+
+    char choice;
+    do
+    {
+        int v;
+        printf("Enter the value to be searched:\n");
+        scanf("%d", &v);
+
+        int index = linearsearch(a, n, v);
+        if (index != -1)
+            printf("Value %d is in the array at index %d.\n", v, index);
+        else
+            printf("Value %d is not in the array.\n", v);
+
+        printf("Search again? (y/n): ");
+        scanf(" %c", &choice);  // The space before %c eats the leftover newline
+    } while (choice == 'y' || choice == 'Y');
 
     free(a);
     return 0;