Removing the last n characters of a string in C++

In this tutorial, we are going to learn about how to remove the last n characters of a string in C++.

Consider, we have the following string.

string car  = "tesla";

Now, we want to remove the last 3 characters sla from the above string and return te.

Removing the last n characters

To remove the last n characters of a string, we can use the built-in erase() function by passing the string.length()-n as an argument to it.

Where n is the number of characters we need to remove from the end of a string.

Here is an example, that removes the last 3 characters from the following string:

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

int main()
{
    string car  = "tesla";
    car.erase(car.length()-3); // removes last 3 characters
    cout<< car;
    return 0;
}

Output:

"te"

Note: The erase() function mutates the original string.

Similarly, we can also use the substr() function to remove the last n characters of a string in C++.

Example:

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

int main()
{
    string car  = "tesla";
    string result = car.substr(0, car.length()-3);
    cout<< result;
    return 0;
}

In the example above, we have passed 0, car.length()-3 to the substr() function. so it begins the extraction at index 0, to the car.length()-3.

The length() function returns the total number of characters in a given string.

Note: The substr() function returns a new string with the specified characters instead of mutating the original string.