Simply adding/removing/sorting data

Question

I wrote a simple data handler class.

I would like to know if I can make my class more simple and efficient for doing the identical feature.

My Code :

#include <iostream>
#include <string>
#include <vector>
using namespace std;
class MyData
{
public:
 void add(const pair<string *, int> &elem)
 {
 size_t index = findIndex(elem.first);
 if (index != -1) //if key exists, update the value
 {
 myVec[index].second = elem.second;
 return;
 }
 myVec.push_back(elem);
 }
 void remove(string *strPtr)
 {
 size_t index = findIndex(strPtr);
 if (index != -1)
 myVec.erase(myVec.begin() + index);
 }
 void sort()
 {
 std::sort(myVec.begin(), myVec.end(), comp);
 }
 void print()
 {
 for (size_t i = 0; i < myVec.size(); ++i)
 {
 cout << *myVec[i].first << " : " << myVec[i].second << '\n';
 }
 }
private:
 size_t findIndex(string *strPtr)
 {
 auto it = find_if(myVec.begin(), myVec.end(), [&](pair<string *, int> const & ref)
 {
 return ref.first == strPtr;
 });
 if (it != myVec.end())
 return std::distance(myVec.begin(), it);
 return -1;
 }
 static bool comp(const pair<string *, int> &a, const pair<string *, int> &b)
 {
 return a.second < b.second;
 }
 vector<pair<string *, int>> myVec;
};
int main()
{
 string fruits[] = {"Apple", "Banana", "Orange", "Grapes", "Lemon"};
 MyData data;
 data.add(make_pair(&fruits[0], 13));
 data.add(make_pair(&fruits[1], 52));
 data.add(make_pair(&fruits[2], 33));
 data.add(make_pair(&fruits[3], 8));
 data.add(make_pair(&fruits[4], 22));
 data.add(make_pair(&fruits[1], 17));
 data.sort();
 data.remove(&fruits[4]);
 data.print();
}

The Result :

Grapes : 8
Apple : 13
Banana : 17
Orange : 33
Program ended with exit code: 0

• Sandro4912: is there any reason to not use a standard container like std::map for the task?
• Zack Lee: @Sandro4912 I couldn't sort values easily&efficiently using std::map so I decided to go with std::vector. Please see my other post: stackoverflow.com/questions/52055430/…

Answer 1

Don't use using namespace std. Its considered bad practice.

See Why is "using namespace std" considered bad practice?

Why pass std::string by pointer? In C++ we have references &. They safe you the burden of dereference the pointers.

Dont use c-style arrays like

string fruits[] = {"Apple", "Banana", "Orange", "Grapes", "Lemon"};

In c++ you can use std::vector or std::array(if the size is fixed) for the task:

std::vector<std::string> fruits = {"Apple", "Banana", "Orange", "Grapes", "Lemon"};

Whats the whole purpose of the structure? You could just use a std::vector> and use std::find and std::sort to accomplish what you want to archieve with youre data structure.