How to Print a String in C++

1. Use std::cout and the << Operator to Print a String
2. Use the std::copy Algorithm to Print a String
3. Use the printf() Function to Print a String
4. Conclusion

Printing strings is a fundamental task in programming, and C++ offers various methods to accomplish this task efficiently and effectively. This article will demonstrate multiple methods of how to print a string in C++.

Use std::cout and the << Operator to Print a String

The std::cout is the global object for controlling the output to a stream buffer. To output the s1 string variable to the buffer, we need to use the operator - << called the stream insertion operator.

The following example demonstrates a single-string output operation.

Example Code:

#include <iostream>
#include <iterator>
#include <string>

using std::cin;
using std::cout;
using std::endl;
using std::string;

int main() {
  string s1 = "This string will be printed";
  cout << s1;
  cout << endl;

  return EXIT_SUCCESS;
}

Output:

This string will be printed

In this code, we begin by including essential libraries, such as <iostream>, <iterator>, and <string>. We then declare a string variable named s1 and assign it the value "This string will be printed".

Next, we use the cout object, part of the Standard Library, to display the content of s1. The << operator is employed to direct the string to the output stream, and following this, we insert endl to create a newline, ensuring that the text is displayed on a new line.

When we execute this program, the output will be This string will be printed followed by a newline.

Use the std::copy Algorithm to Print a String

The copy method is from the <algorithm> STL library, and it can manipulate the range elements in multiple ways. Since we can access the string container itself as a range, we can output each element by adding the std::ostream_iterator<char> argument to the copy algorithm.

Notice that this method can also pass a specific delimiter between each character of the string. In the following code, no delimiter ("") is specified to print the string in its original form.

Example Code:

#include <iostream>
#include <iterator>
#include <string>
#include <vector>

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

int main() {
  string s1 = "This string will be printed";

  copy(s1.begin(), s1.end(), std::ostream_iterator<char>(cout, ""));
  cout << endl;

  return EXIT_SUCCESS;
}

Output:

This string will be printed

In this code, we create a string variable named s1 and assign it the text "This string will be printed". Next, we use the copy function from the Standard Template Library (STL) to output the characters of the string s1.

The copy function is a powerful tool that allows us to manipulate elements within a range. In this case, we specify the range to be from the beginning (s1.begin()) to the end (s1.end()) of the string s1.

To control where the characters are displayed, we use std::ostream_iterator<char>(cout, "").This iterator directs the output to the standard output stream(cout) without any delimiters between characters, thanks to the empty string "".

Finally, we insert cout << endl; to add a newline, ensuring that the printed text appears on a new line in the console. When we run this program, the output will be This string will be printed.

Use the printf() Function to Print a String

The printf is a powerful tool used for formatted output. It is part of the C standard input-output library.

The function can be called from C++ code directly. printf has the variable number of parameters, and it takes string variable as char * type, which means we have to call the c_str method from s1 variable to pass it as an argument.

Note that each type has its format specifier (e.g., string - %s), which is listed in the following table.

Example Code:

#include <iostream>
#include <iterator>
#include <string>

using std::cin;
using std::cout;
using std::endl;
using std::string;

int main() {
  string s1 = "This string will be printed";
  cout << s1;
  cout << endl;

  printf("%s", s1.c_str());
  cout << endl;

  return EXIT_SUCCESS;
}

Output:

This string will be printed
This string will be printed

In this code, we declare a string variable named s1 and assign it the text "This string will be printed". Next, we first use cout, which is the standard output stream, to display the content of s1, and the line cout << s1; effectively prints the string to the console.

Next, we use the printf() function, which is part of the C standard input-output library. It allows us to perform formatted output.

In this case, we use the format specifier %s to indicate that we want to print a string. To use printf() with a C++ string, we must call the c_str() method on the s1 variable to convert it to a C-style string, and this C-style string is then passed as an argument to printf().

Finally, we insert cout << endl; to create a newline, ensuring that the text is displayed on a new line in the console.

When we execute this program, the output will be This string will be printed twice, each followed by a newline. The first line is printed using cout, and the second using printf().

Conclusion

This article has provided various techniques for printing strings in C++. Whether we choose the straightforward std::cout and << operator, the versatile std::copy algorithm, or the powerful printf() function, we have a range of options to suit our specific programming needs and the choice of method ultimately depends on our project’s requirements and personal coding preferences.

By mastering these methods, we’ll be well-equipped to handle string output effectively in our C++ programs.