C If … Else Examples

Real-Life Examples

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

int doorCode = 1337;

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

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

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

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

Find out if a person is old enough to vote:

int myAge = 25;
int votingAge = 18;

if (myAge >= votingAge) {
  printf("Old enough to vote!");
} else {
  printf("Not old enough to vote.");
}

Find out if a number is even or odd:

int myNum = 5;

if (myNum % 2 == 0) {
  printf("%d is even.\n", myNum);
} else {
  printf("%d is odd.\n", myNum);
}