C++

#include  #include  #include  #include  

Implement each of the following methods and functions. Be sure to use const, public, and private in useful and sensible ways.

1. A default constructor str_vec() that creates a new str_vec of size 0 and capacity 10. It can be used like this:

   str_vec arr; // arr is an empty str_vec of size 0 and capacity 10 

2. A constructor str_vec(n s) that creates a new str_vec of size n where each element contains a copy of the string s. It can be used like this:

   str_vec arr(5, "cat"); // arr is str_vec of size 5, each entry contain the string "cat" 

   The capacity of arr should be 5 or more.

   If n is less than 0, use cmpt::error to throw a helpful error message.

3. A copy constructor str_vec(other) that creates a new str_vec that is a copy of the str_vec named other. It can be used like this:

   str_vec a(5, ""); str_vec arr(a); // arr is str_vec of size 5 with each entry equal to the string "" 

   The capacity of arr should be at least the size of the a.

4. A destructor ~str_vec() that deletes all the dynamic memory used by this str_vec.

   Be sure to test your program with valgrind!

5. Write the following three getters:

   • size() returns the size of the str_vec
   • capacity() returns the capacity of the str_vec
   • pct_used() returns the % of the underlying array that is in use, i.e. the size divided by the capacity

   Make sure that these are all const methods!

   They can be used like this:

   str_vec empty; cout << empty.size() << ' ' // 0 << empty.capacity() << ' ' // 10 << empty.pct_used() << ' '; // 0 

6. Write the following three non-mutating methods:

   • to_str() returns a string representation of this str_vec; please use the []-brackets style as shown in the example below.
   • print() is a void method that prints the string representation of this str_vec to cout
   • println() is a void method that does the same thing as print(), but also prints a at the end

   Make sure that these are all const!

   They can be used like this:

   str_vec arr(3, "cat"); string s = arr.to_str(); // s is the string ["cat", "cat", "cat"] arr.print(); // prints ["cat", "cat", "cat"] on cout (no at end) arr.println(); // prints ["cat", "cat", "cat"] on cout ( at end) 

7. Write the following two methods:

   • get(i) is a getter that returns the string at index location of i of the str_vec. Just as with arrays, the first index location is 0. Make sure this is const!
   • set(i, s) is a setter that sets index location i to be a copy of the string s

   For both of these methods, use cmpt::error to throw a helpful error message if the passed-in index i is less than 0, or greater than size()-1.

   They can be used like this:

   str_vec arr(3, "cat"); arr.set(1, "dog"); // arr is now ["cat", "dog", "cat"] string s1 = arr.get(1); // s1 is "dog" string s2 = arr.get(2); // s2 is "cat" 

8. Write the following two mutating methods:

   • append(s) is a void method that adds the string s to the right end (the back) of this str_vec, increasing the size by 1
   • prepend(s) is a void method that adds the string s to the left end (the front) of this str_vec, increasing the size by 1

   For both of these methods, the underlying capacity should only be increased if necessary. If the capacity is increased, it should be doubled.

   They can be used like this:

   str_vec arr; // empty, size 0 arr.append("apple"); // ["apple"] arr.append("orange"); // ["apple", "orange"] arr.prepend("up"); // ["up", "apple", "orange"] arr.prepend("down"); // ["down", up", "apple", "orange"] 

9. Write the following two mutating methods:

   • reverse() is a void method that reverses the order of the elements in this str_vec; please implement this yourself using basic C++, i.e. dont just use std::reverse
   • sort() is a void method that re-arranges all the strings in this str_vec into alphabetical order; please use std::sort() to help do this

   They can be used like this:

   str_vec arr; arr.append("d"); arr.append("b"); arr.append("a"); arr.append("c"); // ["d", "b", "a", "c"] arr.sort(); // ["a", "b", "c", "d"] arr.reverse(); // ["d", "c", "b", "a"] 

10. Write the following two mutating methods:

    • clear() is a void method that removes all elements from this str_vec so its size is 0; the capacity can stay the same
    • shrink_to_fit() is a void method that will, if necessary, re-size the underlying array so that the size and capacity are the same; the elements in the array are not changed in any way

    They can be used like this:

    str_vec arr; // {}, size 0, capacity 10 arr.append("a"); // {"a"}, size 1, capacity 10 arr.append("b"); // {"a", "b"}, size 2, capacity 10 arr.shrink_to_fit(); // {"a", "b"}, size 2, capacity 2 arr.clear(); // {}, size 0, capacity 2 

11. Write the following two functions (not methods!):

    • operator==(a, b) is a bool function that returns true if the str_vec a and the str_vec b have the same elements in the same order, and false otherwise
    • operator!=(a, b) is a bool function that returns true if the str_vec a and the str_vec b dont have the same elements in the same order, and false otherwise

They can be used like this:

str_vec a(3, "cat"); str_vec b(3, "cat"); if (a == b) cout << "same "; // prints "same" if (a != b) cout << "different "; // prints nothing a.set(0, "feline"); if (a == b) cout << "same "; // prints nothing if (a != b) cout << "different "; // prints different