Input and Output
Interactive programs receive information from the user and then display a result. C++ commonly uses cin for simple input, getline() for a complete line of text, and cout for output.
Reading Simple Values
Input with cin
#include <iostream>
#include <string>
using namespace std;
int main()
{
string name;
int age;
cout << "Enter your first name: ";
cin >> name;
cout << "Enter your age: ";
cin >> age;
cout << "Hello, " << name << ". You are "
<< age << " years old." << endl;
return 0;
}Reading Text That Contains Spaces
cin >> normally stops at the first space. Use getline() when the user may enter a full name, address, or sentence.
Input with getline
#include <iostream>
#include <string>
using namespace std;
int main()
{
string fullName;
cout << "Enter your full name: ";
getline(cin, fullName);
cout << "Welcome, " << fullName << "!" << endl;
return 0;
}Input tip
When getline() follows cin >>, you may need cin.ignore() to remove the leftover newline character.
Practice task
Ask the user for a full name and favourite programming language, then display both values in one sentence.
Lesson Summary
Read user input with cin and getline, then display clear output with cout.