C++ Cookbook

4.3. Storing Strings in a Sequence

Problem

You want to store a set of strings in a sequence that looks and feels like an array.

Solution

Use a vector for array-like storage of your strings. Example 4-6 offers a simple example.

Example 4-6. Store strings in a vector

#include <string>
#include <vector>
#include <iostream>

using namespace std;

int main() {

   vector<string> v;

   string s = "one";
   v.push_back(s);

   s = "two";
   v.push_back(s);

   s = "three";
   v.push_back(s);

   for (int i = 0; i < v.size(); ++i)
   {
      cout << v[i] << '\n';
   }
}

vectors follow array semantics for random access (they also do a lot more), so they are easy and familiar to use. vectors are just one of many sequences in the standard library, however; read on for more of this broad subject.

Discussion

A vector is a dynamically sized sequence of objects that provides array-style operator[] random access. The member function push_back copies its argument via copy constructor, adds that copy as the last item in the vector, and increments its size by one. pop_back does the exact opposite, by removing the last element. Inserting or deleting items from the end of a vector takes amortized constant time, and inserting or deleting from any other location takes linear time. These are the basics of vectors. There is a lot more to them.

In most cases, a vector should be your first choice over a C-style array. First of all, they are dynamically sized, which means they can grow as needed. You don’t have to do all sorts of research to figure out ...