Solved-Homework Assignment 3 -Solution

Description

Assignment 3 include a programming portion and a written portion. The programming portion must compile and consist of a single le ( hw03.cpp), and the written portion should consist of a single le (hw03written) in a .pdf format. Be sure to include your name at the beginning of each le! You must hand in both les via NYU Classes.

Programming Part:

1. Write a function template called print if that:

takes three parameters: two iterators start, end, and a functor pred

start and end have the capabilities of a forward iterator, and refer to a range [start,end) in a container

pred is a functor that takes an element in the range [start,end) as an arguement and returns a bool

prints¹ all items in the range [start,end) which evaluates to true

runs in O(n) time where n is the number of items in the range [start,end)

The signature of your function template is:

template< class Itr, class UnaryPred >

void print_if( Itr start, Itr end, UnaryPred pred )

A small amount of extra credit will be given for guring out how to add your own test case to the unit test for this assignment.

A bonus of %5 percent will be given if you turn in this homework assignment by Tues. Sept 27 at 11:00 p.m.

• Print each item on its own line

Written Part

1. For the vector class, and for the following code² snippet:

vector<int> c { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 }; vector<int>::iterator itr1 = c.begin()+2; vector<int>::iterator itr2 = c.begin()+4; vector<int>::iterator itr3 = c.begin()+8;

cout << *(c.begin( ) + ( c.end( ) – c.begin( ) )/2 ) << endl; c.erase(itr2);

cout << *itr1 << endl; cout << *itr2 << endl; cout << *itr3 << endl;

cout << *(c.begin( ) + ( c.end( ) – c.begin( ) )/2 ) << endl; What is printed? Explain your answer.³

2. Using big-Oh notation, give the worst case run time for the method print if, which you implemented programming problem 1.

3. Given the following code snippet:

vector<int> a {1,2,3,4, …, n}; // vector, a, has n items vector<int>::iterator itrStart; vector<int>::iterator itrMid;

vector<int>::iterator itrEnd;

Assign values to the iterators, itrStart, itrMid, itrEnd, so that:

1. 1. [itrStart, itrMid) refers to the range 1,2, 3, …, n/2

1. 2. [itrMid, itrEnd) refers to the range n/2+1,n/2+2, …, n

4. For each code snippet below state either why the code won’t compile/run, or state what is printed by the code snippet.

4. 1. vector<int> a {1, 2, 3, 4, 5}; vector<int>::iterator itra = a.begin(); cout << *(itra + 3);

4. 2. list<int> b {1, 2, 3, 4, 5}; list<int>::iterator itrb = b.begin(); cout << *(itrb + 3);

²Remember c.end() – c.begin() returns the number of items in the range [ c.begin(), c.end() )

• Hint: think of how you implemented the erase method in the Vector class.

3. list<int> c {1, 2, 3, 4, 5}; list<int>::iterator itrc = c.end(); itrc–;

cout << *(itrc);

3. vector<int> d {1, 2, 3, 4, 5}; vector<char>::iterator itrd = d.begin(); cout << *(itrd + 3);

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