C++ User Input

User input is data that a person types while a program runs. The std::cin stream reads that typed data into variables.

Reading one word

The prompt prints first, with no new line after it. std::cin then stores the typed word in name.

#include <iostream>
#include <string>

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

Reading two numbers

One std::cin line reads two numbers here. Each number lands in its own variable, in order.

#include <iostream>
#include <string>

int main() {
  int a;
  int b;
  std::cout << "Enter two numbers: ";
  std::cin >> a >> b;
  std::cout << "Sum: " << a + b << std::endl;
  return 0;
}

Reading a word and a number

std::cin fills the variables in the order listed. The word lands in name and the number lands in age.

#include <iostream>
#include <string>

int main() {
  std::string name;
  int age;
  std::cout << "Name and age: ";
  std::cin >> name >> age;
  std::cout << name << " is " << age << std::endl;
  return 0;
}

Example

#include <iostream>
#include <string>

int main() {
  std::string item;
  int quantity;
  std::cout << "Item and quantity: ";
  std::cin >> item >> quantity;
  std::cout << "Order: " << quantity << " x " << item << std::endl;
  return 0;
}

Key points

A prompt is a short message printed before input is read.
Use std::cin to read typed values into variables.
The >> signs send each typed value into its variable.
std::cin reads values in order, split by spaces.
One std::cin line can fill two variables in order.
Use std::getline to read a whole line, spaces included.

In this example, the prompt prints with no new line after it. std::cin stores the first typed word in item. std::cin stores the number after it in quantity. The last print builds one line from both values.

Note

A prompt printed without std::endl stays on the same line as the next output.

Try it Yourself

Edit the code, then press Run.

Running is simulated · Programiz C++ Compiler

#include <iostream>
#include <string>

int main() {
  std::string item;
  int quantity;
  std::cout << "Item and quantity: ";
  std::cin >> item >> quantity;
  std::cout << "Order: " << quantity << " x " << item << std::endl;
  return 0;
}

Exercise

Which line reads a typed word into a variable named name?

std::cin >> name; std::cout << name; std::string name; std::cout >> name;