SEQUENTIAL SEARCH CODE UPDATE
SEQUENTIAL SEARCH CODE CODE

The answer is to use a list that is larger in size than the number of items by We assume that the item will always be found, how can we test for failure? Of course, that creates the problem of a failed search. This way you can avoid the two termination conditions in the loop inįavor of only one. Of those ways is to assume that the item being searched for will always be in

The basic sequential search algorithm can be improved in a number of ways. :-) The loop terminates if i is a null pointer (theĪlgorithm assumes a null pointer terminates the list) or if the item was found. Idiom should be familiar to most readers. Instead of a counting loop, we use an idiom for walking a linked list. That is because each comparison in a binary search throws away half of the remaining possibilities while each comparison in a sequential search only throws away one possibility.The most obvious algorithm is to start at the beginning and walk to the end, testing for a match at each item:īool jw_search ( int *list, int size, int key, int*& rec ) For example, a million item list will take on average half a million comparisons to find an item by sequential search but, a binary search will take only about twenty comparisons. The advantage of a binary search is that you will find your item much faster but the list must be sorted. The advantage of a sequential search is that your item will eventually be found, even if the list is not sorted.

If the middle is smaller than the lookup item, select the 'larger' side list and repeat the process. If the middle is larger than the lookup item, select the 'smaller' side list and repeat the process.ģc. If the middle matches the lookup item, you found the item in your list.ģb. It is ok to divide two element lists like where 4 is the middle.ģa. If the unsearched part of your list is more than one element, find the element closest to the middle. If it does not match, the item isn't in your list.ģ. If id does match, you found the item in your list.Ģb. If the unsearched part of your list is just one element, then check the element to see if it matches the lookup item.Ģa. If the unsearched part of your list is empty, then determine you didn't find the item.Ģ. If there is no next item, then you searched everything without finding your item.Ī binary search is also simple: 1.

SEQUENTIAL SEARCH CODE UPDATE

If it does not match update the starting index to the item you just checked and continue at step 2.ģ.

If it does match you found the item in your collection.Ģb. If there is a 'next' item, check the next item to see if it matches.Ģa. Set the starting index just before the beginning.Ģ. With that in mind, I'll repeat what you probably have heard just in case it wasn't explained well.Ī sequential search is simple: 1.

SEQUENTIAL SEARCH CODE CODE

Sometimes it is easier to write the code when you have a very strong grasp of the searching techniques at hand. * load the items array with items to be searched through */ Searches the arrays using sequential search and binary search A second array called targets is loaded with 1000 int values (500 values from the items array and 500 values that are not in the items array).īasically, the search needs to go through the items array to look for int values in the targets array. I'm trying to write a program that conducts a sequential search and a binary search in an array called items that has 10000 sorted random int values.

Sequential search code