## Output

We output values to standard output (the screen) using the std::cout command and the << operator:

```#include <iostream>
int main(){
std::cout << "Hello World!" << std::endl;
int x = 123;
std::cout << "The value of x is: " << x << std::endl;
}```

## Input

We can accept values from the standard input using the std::cin function and the >> operator.

```#include <iostream>
int main(){
int x;
std::cout << "Enter the value of x: ";
std::cin >> x;
std::cout << "The value you entered is  " << x << std::endl;
}
```

We can accept multiple values using multiple >> operators:

```#include <iostream>
int main(){
int x, y, z;
std::cout << "Enter the value of x, y and z separated by space: ";
std::cin >> x >> y >> z;
std::cout << "x is: " << x << " y is: " << y << " z is: " << z << std::endl;
}
```

We can input multiple values of different types using one std::cin command:

```#include <iostream>
int main(){
int x;
double d;
char c;
std::cout << "Enter the value of x, d and c separated by space: ";
std::cin >> x >> d >> c;
std::cout << "x is: " << x << " d is: " << d << " c is: " << c << std::endl;
}
```

The above statement of std::cin >> x >> d >> c; is equivalent of multiple std::cin statements:

```std::cin >> x;
std::cin >> d;
std::cin >> c;
```

## String input

When inputting a string we use the std::getline function in combination with std::cin:

```#include <iostream>
#include <string>
int main(){
std::string tempstring;
std::cout << "Enter the string: ";
std::getline(std::cin, tempstring);
std::cout << "You entered: " << tempstring;
```