Input and output operations in C++

Input and output operations in C++ involve reading data from the user (input) and displaying results to the user (output). The standard way of performing these operations is through the use of the cin (for input) and cout (for output) streams.

Let’s explore these concepts:

Input Operations:

Reading Data from the User:

• To read data from the user, you use the cin stream.
  
  Example
  #include <iostream>
 
int main() {
int number;
std::cout << "Enter a number: ";
std::cin >> number;
std::cout << "You entered: " << number << std::endl;
return 0;
}

  In this example, std::cin >> number; reads an integer from the user and stores it in the variable number.

Reading Strings:

• Reading strings is also common using getline or >> for single-word inputs.Example:
  #include <iostream>
#include <string>
int main() {
std::string name;
std::cout << "Enter your name: ";
std::getline(std::cin, name);
std::cout << "Hello, " << name << "!" << std::endl;
return 0;
}

Output Operations:

Displaying Data to the User:

• To output data to the console, you use the cout stream.
  #include <iostream>int main() {
std::cout << "Hello, World!" << std::endl;
return 0;
}In this example, "Hello, World!" is displayed to the console.

Formatting Output:

• You can format the output using manipulators, like setw, setprecision, etc.
  #include <iostream>
#include <iomanip>int main() {
double value = 3.14159;
std::cout << std::fixed << std::setprecision(2) << "Value: " << value << std::endl;
return 0;
}This example sets the precision to two decimal places for the double value.

Error Handling:

• It’s crucial to handle errors during input operations to ensure the program doesn’t break unexpectedly. You can check the state of the stream after an input operation:#include <iostream>int main() {
int number;
std::cout << "Enter a number: ";if (std::cin >> number) {
std::cout << "You entered: " << number << std::endl;
} else {
std::cerr << "Invalid input!" << std::endl;
}

  return 0;
}

  Here, std::cin >> number returns true if the input is successful and false otherwise.