C++ Searching, Sorting, and Pointers
How do you use pointer arithmetic?
*(arrayName + 2);
How does selection sort work?
1. Finds the smallest element in the list and swaps it with the element in the first position. 2. Then it finds the second smallest element and swaps it with the element in the second position. 3. It does this until we reach the last position.
How does bubble sort work?
1. Going left to right, you compare consecutive elements. 2. Whenever two are out of place, you swap them. It keeps going until the largest element is in the last place. It keeps going until there are no swaps
What is a constant pointer?
A pointer whose address cannot change
What is a pointer variable?
A variable that holds an address and allow you to access memory locations
Where does the array name start?
An array name starts at the first element of an array
What is a Basic Step?
An operation in the algorithm that executes in a constant amount of time
How does a linear search work?
It compares the value to each number in an array until it finds the number or until it reaches the end of the array
What is the indirection operator and what does it do?
It is an asterisk and allows you to access the value of a pointer
What are the advantages and disadvantages of bubble sort?
It is easy to understand and implement but it's inefficient and slow for large arrays
What are the advantages and disadvantages of selection sort?
It is more efficient than bubble sort, but some consider it to be harder to understand
How does a binary search work?
It looks at the number in the middle. If the number is higher than the value, we eliminate all the lower values and look only at the higher values. If the number is lower, we eliminate all the higher values and only look at the lower values.
Is bounds checking performed on array access?
No
What is the runtime complexity of bubble sort?
O(N^2)
What is the runtime complexity of selection sort?
O(N^2)
What is a Computation Problem?
Problem solved by an algorithm
What is the efficiency of an algorithm measured by?
Space (computer memory used) Time (how long to execute the algorithm)
What is a disadvantage of binary search?
The array elements must be sorted
When does a binary search end?
The binary search repeats until it finds the value or the low, mid, and high are all the same
How do you find the mid value in a binary search?
You add the low position and the high position and divide by two
How do you print the value of a pointer?
cout << *ptr; //shows the value
How do I display the address of an array?
cout << arrayName; //displays the address
How do I display the value in an array?
cout << array[0]; //shows the first element or cout << *arrayName;
How do you print the address of a pointer
cout << ptr; //shows the address
How do you define a constant pointer?
int * const ptrName = &size;
How do you define a pointer?
int *ptr
How do you assign a pointer?
ptr = #
