Concatenate an integer to a string object in C++

This post will discuss how to concatenate an integer to a string object in C++.

1. Using `to_string()` function

The most commonly used approach to concatenate an integer to a string object in C++ is to call the std::to_string function, which can return the string representation of the specified integer.

#include <iostream>

#include <string>

int main()

{

int i = 17;

std::string s = "C++" + std::to_string(i);

std::cout << s << std::endl;

return 0;

}

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Output:

C++17

2. Using `std::stringstream` function

Another good alternative is to use the std::stringstream. The following C++ program demonstrates it:

#include <iostream>

#include <string>

#include <sstream>

std::string toString(auto &i) {

std::stringstream ss;

ss << i;

return ss.str();

}

int main()

{

int i = 17;

std::string s = "C++" + toString(i);

std::cout << s << std::endl;

return 0;

}

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Output:

C++17

3. Using boost’s `lexical_cast`

We can also use a boost::lexical_cast<> to concatenate an integer to a string object, as shown below:

#include <iostream>

#include <string>

#include <boost/lexical_cast.hpp>

int main()

{

int i = 17;

std::string s = "C++" + boost::lexical_cast<std::string>(i);

std::cout << s << std::endl;

return 0;

}

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Output:

C++17

That’s all about concatenating an integer to a string object in C++.

Concatenate an integer to a string object in C++

1. Using to_string() function

2. Using std::stringstream function

3. Using boost’s lexical_cast

Share this:

1. Using `to_string()` function

2. Using `std::stringstream` function

3. Using boost’s `lexical_cast`