How to Convert Int to ASCII Char in C++

1. Use int to char Assignment to Convert int to ASCII char
2. Use the sprintf() Function to Convert int to ASCII char
3. Use Type Casting to Convert int to ASCII char
4. Conclusion

This article will explain several methods of how to convert int to ASCII char in C++. From straightforward int to char assignment to using printf, sprintf, and type casting, each method is examined, offering flexibility to suit various programming needs.

Use int to char Assignment to Convert int to ASCII char

ASCII character encoding is specified in a 7-bit format. Thus, there are 128 unique characters, each mapping to the corresponding numeric value from 0 to 127.

Since the C programming language implemented char types as numbers underneath the hood, we can assign an int variable to a char type variable and treat that as the corresponding ASCII character. For example, we directly push values from the int vector to the char vector and then output them using the std::copy method, displaying ASCII characters as expected.

Note that assigning to char type only works when the int value corresponds to an ASCII code, e.i. is in the range 0-127.

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

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

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

  std::copy(numbers.begin(), numbers.end(),
            std::ostream_iterator<int>(cout, "; "));

  chars.reserve(numbers.size());
  for (auto &number : numbers) {
    chars.push_back(number);
  }
  cout << endl;
  std::copy(chars.begin(), chars.end(),
            std::ostream_iterator<char>(cout, "; "));

  return EXIT_SUCCESS;
}

Output:

97; 98; 99; 100; 101; 102; 103; 
a; b; c; d; e; f; g;

In the code above, we start by defining a vector named numbers, containing integer values corresponding to ASCII codes for characters 'a' to 'g'. Using the std::copy function, we print the original integer values to the console separated by semicolons and spaces.

Following this, we create an empty vector called chars to store ASCII characters. We then optimize memory usage by reserving space in the chars vector based on the size of the numbers vector.

In a subsequent loop, we iterate through each integer in the numbers vector and use the push_back method to populate the chars vector with ASCII characters corresponding to the integers. Finally, we employ another std::copy function to print the converted ASCII characters to the console, again separated by semicolons and spaces.

The program concludes by printing a newline character for better formatting. This code demonstrates an effective way to convert and display both original integer values and their corresponding ASCII characters concisely.

Alternatively, we can directly output int values as ASCII characters using the printf function. printf takes format specifier for the corresponding type argument, as shown in the following table.

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

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

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

  for (const auto &number : numbers) {
    printf("%c; ", number);
  }
  cout << endl;

  return EXIT_SUCCESS;
}

Output:

a; b; c; d; e; f; g;

In this code snippet, we begin by initializing a vector called numbers containing integer values corresponding to ASCII codes for characters 'a' to 'g'. Subsequently, we iterate through each element in the numbers vector using a for loop.

Within the loop, we use the printf function to print each integer as its corresponding ASCII character, followed by a semicolon and a space. This concise code efficiently outputs the ASCII characters associated with the given integer values to the console.

Finally, we utilize cout to print a newline character, enhancing the output’s readability. The code concludes with a successful exit status denoted by EXIT_SUCCESS.

Use the sprintf() Function to Convert int to ASCII char

The sprintf function is another method to convert int values to characters. We must declare a char variable to hold the converted value.

This variable is passed as the first argument to sprintf, and the third parameter specifies the number to be processed. Finally, you should provide one of the format specifiers, as with printf, it indicates the type to which the value will be converted.

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

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

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

  array<char, 5> char_arr{};
  for (auto &number : numbers) {
    sprintf(char_arr.data(), "%c", number);
    printf("%s; ", char_arr.data());
  }
  cout << endl;

  return EXIT_SUCCESS;
}

Output:

a; b; c; d; e; f; g;

In this code, we initialize a vector called numbers containing integers representing ASCII codes for characters 'a' to 'g'. Additionally, we declare an array named char_arr capable of storing up to 5 characters.

Within a for loop, we iterate through each integer in the numbers vector. Using the sprintf function, we convert each integer to its corresponding ASCII character and store it in the char_arr array.

Subsequently, we utilize printf to print the converted ASCII character, followed by a semicolon and a space. This process is repeated for each integer in the vector.

Finally, we use cout to print a newline character, enhancing the output’s readability. The program concludes with a successful exit status denoted by EXIT_SUCCESS.

Use Type Casting to Convert int to ASCII char

Using type casting to convert an integer to an ASCII character involves casting the integer value to a char type.

Keep in mind that this method assumes that the integer value is within the valid ASCII range (0 to 127). If the integer is outside this range, the result might not represent a valid ASCII character.

Additionally, the behavior is undefined if you try to convert a negative integer to a char using this method.

#include <iostream>
#include <vector>

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

  for (const auto &number : numbers) {
    char asciiChar = static_cast<char>(number);
    std::cout << asciiChar << "; ";
  }
  std::cout << "\n\n";

  return EXIT_SUCCESS;
}

Output:

a; b; c; d; e; f; g;

In this code snippet, we initialize a vector named numbers containing integers representing ASCII codes for characters 'a' to 'g'. Using a for loop, we iterate through each integer in the numbers vector.

Inside the for loop, we employ type casting (static_cast<char>) to convert each integer to its corresponding ASCII character, storing the result in a variable named asciiChar. We then use std::cout to print the ASCII character followed by a semicolon and a space.

This process is repeated for each integer in the vector, producing a clear and concise output. Finally, we use std::cout to print two newline characters for better formatting.

The program concludes with a successful exit status denoted by EXIT_SUCCESS.

Conclusion

The article explores different methods to convert integers to ASCII characters in C++.

The first method employs int to char assignment, utilizing the numeric nature of char types. The second method uses the printf function with %c format specifiers for direct conversion.

Another approach involves the sprintf function for integer-to-character conversion. Lastly, type casting is demonstrated, directly converting integers to char types.

Each method provides distinct strategies for achieving the conversion, catering to different programming scenarios.