C++ Output (Print Text)
In C++, printing text to the console is done using the standard output stream, which is represented by std::cout
. This chapter will guide you through the basics of outputting text in C++ and provide examples to illustrate different scenarios.
1. Basic Output
The simplest way to print text in C++ is to use the std::cout
object along with the insertion operator <<
. Here’s an example:
#include <iostream>
int main() {
std::cout << "Hello, World!" << std::endl;
return 0;
}
Explanation:
#include <iostream>
: Includes the input-output stream library needed forstd::cout
.std::cout << "Hello, World!" << std::endl;
: Prints “Hello, World!” followed by a newline.
2. Printing Variables
You can also print the value of variables using std::cout
. Here’s an example:
#include <iostream>
int main() {
int age = 25;
std::cout << "I am " << age << " years old." << std::endl;
return 0;
}
Explanation:
int age = 25;
: Declares an integer variableage
and assigns it the value 25.std::cout << "I am " << age << " years old." << std::endl;
: Prints the string “I am “, the value ofage
, and the string ” years old.” followed by a newline.
3. Formatting Output
C++ allows you to format your output in various ways. Here are some examples:
3.1. Printing Multiple Lines
#include <iostream>
int main() {
std::cout << "Line 1" << std::endl;
std::cout << "Line 2" << std::endl;
std::cout << "Line 3" << std::endl;
return 0;
}
3.2. Using Escape Sequences
#include <iostream>
int main() {
std::cout << "Hello, World!\n"; // Newline
std::cout << "Hello,\tWorld!" << std::endl; // Tab
std::cout << "Hello, \"World!\"" << std::endl; // Double quote
return 0;
}
4. Combining Text and Variables
Combining text and variables in your output can be very useful. Here is an example:
#include <iostream>
int main() {
std::string name = "John";
int age = 30;
std::cout << "Name: " << name << ", Age: " << age << std::endl;
return 0;
}
Explanation:
std::string name = "John";
: Declares a string variablename
and assigns it the value “John”.int age = 30;
: Declares an integer variableage
and assigns it the value 30.std::cout << "Name: " << name << ", Age: " << age << std::endl;
: Prints “Name: “, the value ofname
, “, Age: “, and the value ofage
followed by a newline.
5. Outputting Boolean Values
When printing boolean values, C++ outputs 1 for true
and 0 for false
by default:
#include <iostream>
int main() {
bool flag = true;
std::cout << "Flag is " << flag << std::endl;
return 0;
}
To print true
and false
as text, you can use the std::boolalpha
manipulator:
#include <iostream>
int main() {
bool flag = true;
std::cout << std::boolalpha;
std::cout << "Flag is " << flag << std::endl;
return 0;
}
6. Outputting Floating-Point Numbers
C++ provides ways to control the precision and format of floating-point numbers:
#include <iostream>
#include <iomanip>
int main() {
double num = 123.456789;
std::cout << "Default: " << num << std::endl;
std::cout << "Fixed: " << std::fixed << num << std::endl;
std::cout << "Scientific: " << std::scientific << num << std::endl;
std::cout << "Precision 2: " << std::setprecision(2) << num << std::endl;
return 0;
}
Conclusion
This chapter covered the basics of outputting text in C++ using std::cout
. By mastering these techniques, you can effectively display information and debug your programs. Experiment with different formats and manipulators to enhance your output capabilities.