C++ is among the most robust programming languages available at the moment. After all, it rarely crashes, as long as you know what you are doing. The keyword is “knowing what you are doing”, as its robustness means that you must learn everything from the ground up.

One such necessary knowledge is how to convert ASCII to char in C++.

How To Convert ASCII to Char in C++

With Assignment Operator

The first method we will introduce to you is also the most approachable one. It relies on the ASCII’s encoding nature of 128 unique characters corresponding to specific character values.

Standing alone, it’s nothing impressive, but when we consider the fact that all C programming languages implement char as numbers under the hood, things change drastically. Now, we can assign unique int values to specific char values.

In other words, we can just convert the ASCII value to char simply by assigning them. This method is quick and reliable, but it does have a fatal weakness of being restricted to a 0-127 range. After all, it does rely on the ASCII encoding, so it can only use the 128 default values.

You can see it being used in checking strings for numbers.

#include <iostream> 
#include <vector> 
#include <iterator>
#include <charconv> 

using std::cout; 
using std::vector; 
using std::endl; 
using std::copy; 

int main() { 
    vector<int> ascii_vals {97, 98, 99, 100, 101, 102, 103}; 
    vector<char> chars {}; 
    chars.reserve(ascii_vals.size()); 

    for (auto &n : ascii_vals) { 
        chars.push_back(n); 
    } 

    copy(chars.begin(), 
    chars.end(), 
    std::ostream_iterator<char>(cout, "; ")); 

    return EXIT_SUCCESS; 
}

With sprintf()

Another approach to this problem is to make use of sprintf() to convert ASCII to char in C++. sprintf() is a special function integrated into C++, which will send formatted output to anywhere its str variable points to.

Its working principle is to first declare an array of the interested type and store all the converted values in it. This action will keep on happening until printf starts outputting to the console.

You will need to put in a format specifier denoting your character value so that the machine knows what to convert into.

This method is one of the fastest currently known, but it also carries some huge weaknesses. The most vital one is sprint() ‘s limitation in buffer size. You will need to watch it closely, as once buffer overflow happens, crashing is the least of your worries.

Buffer overflows can create significant holes in your code’s security, allowing malicious codes to execute freely. Any experienced programmer knows how big of a problem this can cause, so we recommend being as careful as possible while using this method.

#include <iostream> 
#include <vector> 
#include <array> 
#include <iterator> 
#include <charconv> 

using std::cout;
using std::vector; 
using std::endl; 
using std::array; 
using std::copy; 
using std::to_chars; 

int main() { 
    vector<int> ascii_vals {97, 98, 99, 100, 101, 102, 103}; 
    array<char, 5> char_arr{}; 

    for (auto &n : ascii_vals) { 
        sprintf(char_arr.data(), "%c", n); 
        printf("%s; ", char_arr.data()); 
    }

    cout << endl; 
    return EXIT_SUCCESS; 
}

With char()

The last method that you can use to convert ASCII to char in C++ is to use its char() function. Its only weakness is that it can only execute one at a time, so you will need to use a loop if there are a lot of data to convert.

#include <iostream> 
#include <vector>
#include <iterator> 
#include <charconv> 

using std::cout; 
using std::vector; 
using std::endl; 
using std::copy; 

int main() { 
    vector<int> ascii_vals {97, 98, 99, 100, 101, 102, 103}; 

    for (auto &n : ascii_vals) { 
        cout << char(n) << endl; 
    } 

    return EXIT_SUCCESS;
}

Conclusion

This guide on how to convert ASCII to char in C++ has provided you with a total of three approaches. We hope that you can master all of them, as each has specific cases where it shines the most. We do want to note that the second approach needs you to be careful the most, but the rewards are also incredible.