Real-Life Examples

Real Life Example

This example shows how you can use if..else to "open a door" if the user enters the correct code:

Example

int doorCode = 1337;

if (doorCode == 1337) {
  cout << "Correct
code.\nThe door is now open.\n";
} else {
  cout << "Wrong
code.\nThe door remains closed.\n";
}

This example shows how you can use if..else to find out if a number is positive or negative:

Example

int myNum = 10; // Is this a positive or negative number?

if (myNum >
0) {
  cout << "The value is a positive number.\n";
} else if
(myNum < 0) {
  cout << "The value is a negative number.\n";
} else
{
  cout << "The value is 0.\n";
}

Find out if a person is old enough to vote:

Example

int myAge = 25;
int votingAge = 18;

if (myAge >= votingAge) {

cout << "Old enough to vote!\n";
} else {
  cout << "Not old enough
to vote.\n";
}

Find out if a person is old enough to vote, and if they are a citizen (using nested if statements):

Example

int age = 20;
bool isCitizen = true;

if (age >= 18) {
  cout << "Old enough to vote.\n";

  if (isCitizen) {
    cout << "And you are a citizen, so you can vote!\n";
  } else {
    cout << "But you must be a citizen to vote.\n";
  }
} else {
  cout << "Not old enough to vote.\n";
}

Find out if a number is even or odd:

Example

int myNum = 5;

if (myNum % 2 == 0) {
  cout << myNum << " is
even.\n";
} else {
  cout << myNum << " is odd.\n";
}

Check temperature (Celsius):

Example

int temperature = 30;

if (temperature < 0) {
  cout << "It's freezing!\n";
} else if (temperature < 20) {
  cout << "It's cool.\n";
} else {
  cout << "It's warm.\n";
}