What is the drawback to using std::string over std::string_view?

April 19, 2022

I’m trying to store the content of one string into others. I will have a large number of strings, transferring content in short periods of time, however, I’m questioning the suitability of my method.

For small applications, std::string works fine, but how would this affect my method under larger cases (in terms of memory)?

#include <iostream>
#include <string>
using namespace std;
  

int main()
{
    char str_a[]{ "Example String" };
  
    string str_b{ str_a };
    string str_c{ str_b };
  
    // Print the string
    cout << str_a << '\n'
         << str_b << '\n'
         << str_c << '\n';
  
    return 0;
}

OUTPUT:
Example String
Example String
Example String

How would my method benefit if I were to use std::string_view in terms of memory?

>Solution :

std::string uses static memory allocation which causes overhead on memory when assigning the content to another string.
Your current opperation has std::string performing overheads on the memory twice. If your goal is to simply read the string, there is no need for a write operation to be used.
Instead of assigning memory multiple times you could use std::string_view to negate this.

Here’s an example:

#include <iostream>
using namespace std;
#include <string_view>
  
// Driver code
int main()
{

    string_view str_1{ "Example String" };
  
   
    string_view str_2{ str_1 };
  
  
    string_view str_3{ str_2 };
  
    std::cout << str_1 << '\n' << str_2 << '\n' << str_3 << '\n';
    return 0;
}

This gives you the same output as before, but this time no more copies of the string, stored in memory.

The std::string_view provides a lightweight object that offers read-only access to a string or a part of a string using an interface similar to the interface of std::_string and merely refers to the shared char sequence.