Prev Next

Handling User Input in C++

In C++, user input is handled using the std::cin object along with the extraction operator >>. This allows programs to receive input from the user via the console.

Key Topics

Using std::cin

The std::cin object is used to receive input from the user. It works with fundamental data types like integers, floats, characters, etc.

Example: Receiving an Integer Input

#include <iostream>

int main() {
    int age;
    std::cout << "Enter your age: ";
    std::cin >> age;
    std::cout << "Your age is " << age << std::endl;
    return 0;
}

Output:

Enter your age: 25

Your age is 25

Explanation: The program prompts the user to enter their age. The input is stored in the variable age and then displayed back to the user.

Key Takeaways

  • std::cin is used for user input in C++.
  • The extraction operator >> reads input from the console.
  • Ensure the data type of the variable matches the expected input.

Input with Different Data Types

You can receive input of various data types using std::cin. It's important to declare the variable with the correct data type.

Example: Receiving Multiple Inputs

#include <iostream>

int main() {
    int age;
    double salary;
    char grade;
    
    std::cout << "Enter your age: ";
    std::cin >> age;
    
    std::cout << "Enter your salary: ";
    std::cin >> salary;
    
    std::cout << "Enter your grade: ";
    std::cin >> grade;
    
    std::cout << "Age: " << age << ", Salary: " << salary << ", Grade: " << grade << std::endl;
    
    return 0;
}

Output:

Enter your age: 28

Enter your salary: 50000.50

Enter your grade: A

Age: 28, Salary: 50000.5, Grade: A

Explanation: The program receives inputs of different data types and displays them. It demonstrates how std::cin can handle multiple inputs sequentially.

Key Takeaways

  • Declare variables with the appropriate data types for the expected input.
  • Order of input matters when using std::cin sequentially.
  • Be cautious of input buffer issues when mixing data types.

Using getline() for Strings

To read a full line of text, including spaces, use the std::getline() function.

Example: Receiving a String Input

#include <iostream>
#include <string>

int main() {
    std::string fullName;
    
    std::cout << "Enter your full name: ";
    std::getline(std::cin, fullName);
    
    std::cout << "Hello, " << fullName << "!" << std::endl;
    
    return 0;
}

Output:

Enter your full name: Durai Vijayakanth

Hello, Durai Vijayakanth!

Explanation: std::getline() reads an entire line from the input buffer, allowing the user to input strings that contain spaces.

Key Takeaways

  • Use std::getline() to read strings with spaces.
  • Include the <string> header when working with std::string.
  • Be aware of input buffer issues when mixing std::cin and std::getline().
Prev Next