Linux part done.

06/lab6.c

@@ -3,45 +3,56 @@
 #include <stdlib.h>
 #include <pthread.h>
 
-int search_key;
-int search_key_index;
+int array_size = 0;
+int element = 0;
+int num_search_keys = 0; /* Counter for how many times a search key is found. */
+int search_key = 0;
+int search_key_index = 0; /* The index where the search key is in the array. */
+int partitions = 0; /* How to split up the array 2^n times. */
 int* array;
-int array_size;
-int partitions;
-int element;
 
 void sequential_search(void*);
 
 int main(int argc, char** argv) {
     array_size = (int)pow(2, atoi(argv[1]));
+    array = malloc(sizeof(int) * array_size);
     partitions = (int)pow(2, atoi(argv[2]));
-    element = 0;
+    pthread_t* threads = malloc(sizeof(pthread_t) * partitions);
     int i;
+    int partition_size = (array_size/partitions);
     int return_value;
     int search_key_counter;
-    int partition_size = array_size/partitions;
-    pthread_t* search_threads = malloc(sizeof(pthread_t) * partitions);
-    array = malloc(sizeof(int) * array_size);
-    search_key = atoi(argv[3]);
+    long seconds;
+    long milliseconds;
+    long time_elapsed;
+    struct timeval start;
+    struct timeval end;
 
-    printf("array size: %d\n", array_size);
-    printf("partitions: %d\n", partitions);
+    /* Start timing the search. */
+    gettimeofday(&start, NULL);
 
+    /* Entropy for RNG. */
     srand(time(0));
 
+    /* Search key will be a random number between 0-2^n */
+    search_key = rand() % array_size;
+
     for(i = 0; i < array_size; i++) {
-        array[i] = rand();
-        printf("array[%d]: %d\n", i, array[i]);
+        /* Creates random numbers to insert into the array that are between 0-2^n. */
+        array[i] = rand() % array_size;
     }
 
-    printf("\n");
+    printf("The search key is: %d\n\n", search_key);
 
     for(i = 0; i < partitions; i++) {
+        /* Array to pass the start and end indicies for splitting up the array into partitions. */
         int *thread_args = malloc(sizeof(int) * 2);
+
         thread_args[0] = element;
         element += partition_size;
         thread_args[1] = element;
-        return_value = pthread_create(&search_threads[i], NULL, (void *)sequential_search, (void *)thread_args);
+
+        return_value = pthread_create(&threads[i], NULL, (void *)sequential_search, (void *)thread_args);
 
         if(return_value < 0) {
             perror("Cannot create a thread");
@@ -50,15 +61,34 @@ int main(int argc, char** argv) {
     }
 
     for(i = 0; i < partitions; i++) {
-        pthread_join(search_threads[i], NULL);
+        pthread_join(threads[i], NULL);
     }
 
+    /* End timing of the search. */
+    gettimeofday(&end, NULL);
+
+    /* Final check for the search key within the array. */
     for(i = 0; i < array_size; i++) {
         if(array[i] == search_key) {
-            printf("Final search key found at element %d!\n", i);
+            printf("Search key found at element %d in the final search!\n", i);
+            printf("array[%d] = %d\n\n", i, array[i]);
         }
     }
 
+    /* Displays and error if the search key is found more than once. */
+    if(num_search_keys > 1) {
+        printf("There was an error in the search and the search key was found in the array more than once!\n\n");
+    }
+    else if(num_search_keys == 0) {
+        printf("The search key was not found!\n\n");
+    }
+
+    seconds = end.tv_sec - start.tv_sec;
+    milliseconds = end.tv_usec - start.tv_usec;
+    time_elapsed = (((seconds * 1000) + milliseconds)/1000.0) + 0.5;
+
+    printf("Time elapsed: %ld ms\n", time_elapsed);
+
     free(array);
 
     return 0;
@@ -70,12 +100,13 @@ void sequential_search(void* args) {
     int end = search_args[1];
     int i;
 
+    /* Search the array sequentially in O(n) time from the split partition of the array. */
     for(i = start; i < end; i++) {
-        printf("element %d: %d\n", i, array[i]);
-
         if(array[i] == search_key) {
             printf("Search key found at element %d!\n", i);
+            printf("array[%d] = %d\n\n", i, array[i]);
             search_key_index = i;
+            num_search_keys++;
         }
     }
 }