Input and Output

C++ handles console input and output through streams: cout sends data to the screen, and cin reads data typed by the user.

Printing With cout

The insertion operator << sends values into the output stream, and can be chained to print multiple values in one statement. std::endl inserts a newline and flushes the output buffer.

#include <iostream>
#include <string>

int main() {
    std::string name;
    int age;

    std::cout << "Enter your name: ";
    std::cin >> name;

    std::cout << "Enter your age: ";
    std::cin >> age;

    std::cout << name << " is " << age << " years old." << std::endl;
    return 0;
}

Reading Full Lines

The extraction operator >> stops at whitespace, so it cannot read a full sentence containing spaces. Use std::getline() when you need an entire line of text, such as a full name or address.

std::string fullName;
std::cout << "Enter your full name: ";
std::getline(std::cin, fullName);
std::cout << "Hello, " << fullName << "!" << std::endl;

Common Mistakes

• Using cin >> to read a name with spaces, which only captures the first word.
• Mixing cin >> and getline() without clearing the leftover newline character, causing the next getline() to read an empty line.
• Forgetting #include <string> when reading into a std::string.
• Not prompting the user before reading input, leaving them unsure what to type.