Question

Hi, I have C++ programming problem here:

Problem:

Please modify your string type vector in for push_back() function as below:

void push_back(string str)
{
// increase vector size by one
// initialize the new element with str
}

In addition, the standard library vector doesn't provide push_front(). Implement
push_front() for your vector. Test your code with the main function below.

int main()
{
   vector v1(3);
   cout<<"v1: ";
   v1.print(); // this should display -, -, -
   for (int i=0; i    string s = NumberToString(i);
   v1[i]= s;
   }
   v1.push_back(“back”);
   v1.push_front(“front”);
   v1.print(); // this should display front, 1, 2, 3, back
}

Solution:

Actually I have tried. Here is my program (containing class.h, class.cpp, and main.cpp file) :

Class definition file (labten.h) Class implementation file (labten.cpp) Client file (main.cpp) 2 3 4 #ifndef LABTEN_H #define LABTEN_H #include <string> 4 5 #include <iostream> include <string> include "Labten.h" using namespace std; 4 S #include <string> include <iostream> #include <stream) Winclude "labten." using namespace std; 6 7 7 // destructor , deallocates memory string NumbertoString(int number); class vector { private: int sz; // the size std::string elem; // pointer to elements public: vector(int s) 182(s), elem(new std::string[]) { for (int i = 0; i < sz;+i) { elom[1] = "-"; vector: -vector { if (elen) { delete[] elem; ) ) 1e 10 11 // constructor 12 13 13 int main() { vector vi(3); cout << "vi: "; vi.print(); // this should display - for (int i = 0; i <v1.size(); Hi) { strings = NumbertoString(i); vi[i] = s; string vector::get(int n) { return elemin); } 14 15 16 18 19 2e void vector::set(int n, string v) { + (n < sz) { int 1. sz . 1 for (i >= (n - 1); ++i) { elem[i + 1] = elem[1]; vi.push_back("back"); vi.print(); 20 -vector(); // destructor , deallocates memory std::string get(int n); void set(int n, std::string v); // set values int size() const // the number of elements void print(); void push_back(stdirstring); void push_front(std::string): vector(const vector v); vector& operator = (const vector& v); std::string& operator[](int index); } 21 23 elen[i] = v; 23 string NumbertoString(int number) { ostringstream ss; ss << number; return ss.str(); 25 25 26 25 ) ) 26 28 endir 27 28 29 int vector::size() const { return ; } 31 32 void vector::print() { for (int i = 0; i < 51;++){ cout << elen[i] << ", "; cout<<endl; 35 36 37 38 39 48 41 42 vold vector::push_back(const string bstr) { /int sz+1; //std::cout << "C="<<<<< '\n'; elem[sz+1] - bstr; 1 1 std::cout << elem[s2+1); } Trying to store here, but not printing. Why? How to fix it? 43 44 void vector::push_front(const string fstr) { 46 47 ) vector::vector (const vector Sv) { elem = new string[v.52]; ) { for (int i = 3; i < $2;+ elem[2] = v.elem[1]; 53 ] 55 56 58 vector Svector :: operator (const vector &v) { deletel] elem; SE V.52; olem = new string(s); for (int i = 0;i< 52;++) elen[i] - V.elem[i]; 60 return this; 63 65 66 (int index) { 68 69 78 string &vector::operator 3+ (index >= sz) { return elem[@]; ) return elem[index]; }

I have tried to store (line 37-42 at labten.cpp file), but it's not printing.

Therefore, can you please help me to fix it?

Note: if you need, you can get the three files source codes from my google drive folder here:

https://drive.google.com/open?id=1p1EC-lL0-lQU2icMfUvzI9izoR7lU5NK

Thank you.

Best Regards

Answer 1

Here is the c++ code for above problem

#include<iostream>
#include<String>
#include<vector>
#include<sstream>
using namespace std;

class Vector
{
   public:
       vector<string> elements;
       Vector(int size)
       {
           elements.reserve(size);
       }
       void push_back(string);
       void push_front(string);
       void print();
       void insert(int,string);
};

void Vector::push_back(string element)
{
elements.push_back(element);  
}
void Vector::insert(int index,string element)
{
elements.insert(elements.begin()+index,element);
}
void Vector::push_front(string element)
{
elements.insert(elements.begin(),element);
}

void Vector::print()
{
   for(unsigned int i = 0;i<elements.size();++i)
   {
       cout<<elements[i]<<",";
   }
}

int main()
{

   Vector v1(3);
   for(int i=0;i<10;++i)
   {
       stringstream ss;
       ss<<i;
       string s= ss.str();
       v1.insert(i,s);
   }
   v1.push_front("back");
   v1.push_back("front");
   v1.print();
   return 0;
}

Here I have implemented three methods

1. push_back() to push string element in the back of the vector

2. push_front() to push string element in the front of the vector using inbuilt vector function insert

3. insert() this methods inserts a value at any specified location in the vector

The class contains one vector<string> internally to manage all the elements and sstream is used to convert numbers to string.