Menu
×
   ❮   
HTML CSS JAVASCRIPT SQL PYTHON JAVA PHP HOW TO W3.CSS C C++ C# BOOTSTRAP REACT MYSQL JQUERY EXCEL XML DJANGO NUMPY PANDAS NODEJS R TYPESCRIPT ANGULAR GIT POSTGRESQL MONGODB ASP AI GO KOTLIN SASS VUE DSA GEN AI SCIPY AWS CYBERSECURITY DATA SCIENCE
     ❯   

C Real-Life Examples


Practical Examples

This page contains a list of practical examples used in real world projects.


Variables and Data Types

Example

Use variables to store different data of a college student:

// Student data
int studentID = 15;
int studentAge = 23;
float studentFee = 75.25;
char studentGrade = 'B';

// Print variables
printf("Student id: %d\n", studentID);
printf("Student age: %d\n", studentAge);
printf("Student fee: %f\n", studentFee);
printf("Student grade: %c", studentGrade);
Try it Yourself »

Example

Calculate the area of a rectangle (by multiplying the length and width)

// Create integer variables
int length = 4;
int width = 6;
int area;

// Calculate the area of a rectangle
area = length * width;

// Print the variables
printf("Length is: %d\n", length);
printf("Width is: %d\n", width);
printf("Area of the rectangle is: %d", area);
Try it Yourself »

Example

Use different data types to calculate and output the total cost of a number of items:

// Create variables of different data types
int items = 50;
float cost_per_item = 9.99;
float total_cost = items * cost_per_item;
char currency = '$';

// Print variables
printf("Number of items: %d\n", items);
printf("Cost per item: %.2f %c\n", cost_per_item, currency);
printf("Total cost = %.2f %c\n", total_cost, currency);
Try it Yourself »

Example

Calculate the percentage of a user's score in relation to the maximum score in a game:

// Set the maximum possible score in the game to 500
int maxScore = 500;

// The actual score of the user
int userScore = 420;

// Calculate the percantage of the user's score in relation to the maximum available score
float percentage = (float) userScore / maxScore * 100.0;

// Print the percentage
printf("User's percentage is %.2f", percentage);
Try it Yourself »

For a tutorial about variables and data types in C, visit our Variables Chapter and Data Types Chapter.


Booleans

Example

Find out if a person is old enough to vote:

int myAge = 25;
int votingAge = 18;

printf("%d", myAge >= votingAge); // Returns 1 (true), meaning 25 year olds are allowed to vote!
Try it Yourself »

You could also wrap the code above in an if...else to perform different actions depending on the result:

Example

Output "Old enough to vote!" if myAge is greater than or equal to 18. Otherwise output "Not 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.");
}
Try it Yourself »

For a tutorial about booleans in C, visit our Booleans Chapter.


Conditions (If..Else)

Example

Use if..else statements to output some text depending on what time it is:

int time = 20;
if (time < 18) {
  printf("Good day.");
} else {
  printf("Good evening.");
}
Try it Yourself »

Example

Check whether 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.");
}
Try it Yourself »

Example

Find out if a number is positive or negative:

int myNum = 10;

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.");
}
Try it Yourself »

Example

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.");
}
Try it Yourself »

Example

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);
}
Try it Yourself »

For a tutorial about conditions in C, visit our If..Else Chapter.


Switch

Example

Use the weekday number to calculate and output the weekday name:

int day = 4;

switch (day) {
  case 1:
    printf("Monday");
    break;
  case 2:
    printf("Tuesday");
    break;
  case 3:
    printf("Wednesday");
    break;
  case 4:
    printf("Thursday");
    break;
  case 5:
    printf("Friday");
    break;
  case 6:
    printf("Saturday");
    break;
  case 7:
    printf("Sunday");
    break;
}
Try it Yourself »

For a tutorial about switch in C, visit our Switch Chapter.


While Loops

Example

Use a while loop to create a simple "countdown" program:

int countdown = 3;

while (countdown > 0) {
  printf("%d\n", countdown);
  countdown--;
}

printf("Happy New Year!!\n");
Try it Yourself »

Example

Use a while loop to play a game of Yatzy:

int dice = 1;

while (dice <= 6) {
  if (dice < 6) {
    printf("No Yatzy\n");
  } else {
    printf("Yatzy!\n");
  }
  dice = dice + 1;
}
Try it Yourself »

Example

Use a while loop to reverse some numbers:

// A variable with some specific numbers
int numbers = 12345;

// A variable to store the reversed number
int revNumbers = 0;

// Reverse and reorder the numbers
while (numbers) {
  // Get the last number of 'numbers' and add it to 'revNumber'
  revNumbers = revNumbers * 10 + numbers % 10;
  // Remove the last number of 'numbers'
  numbers /= 10;
}
Try it Yourself »

For a tutorial about while loops in C, visit our While Loop Chapter.


For Loops

Example

Use a for loop to create a program that only print even values between 0 and 10:

int i;

for (i = 0; i <= 10; i = i + 2) {
  printf("%d\n", i);
}
Try it Yourself »

Example

Use a for loop to create a program that counts to 100 by tens:

for (i = 0; i <= 100; i += 10) {
  printf("%d\n", i);
}
Try it Yourself »

Example

Use a for loop to create a program that prints the multiplication table of a specified number (2 in this example):

int number = 2;
int i;

// Print the multiplication table for the number 2
for (i = 1; i <= 10; i++) {
  printf("%d x %d = %d\n", number, i, number * i);
}

return 0;
Try it Yourself »

For a tutorial about for loops in C, visit our For Loop Chapter.


Arrays

Example

Create a program that calculates the average of different ages:

// An array storing different ages
int ages[] = {20, 22, 18, 35, 48, 26, 87, 70};

float avg, sum = 0;
int i;

// Get the length of the array
int length = sizeof(ages) / sizeof(ages[0]);

// Loop through the elements of the array
for (int i = 0; i < length; i++) {
  sum += ages[i];
}

// Calculate the average by dividing the sum by the length
avg = sum / length;

// Print the average
printf("The average age is: %.2f", avg);
Try it Yourself »

Example

Create a program that finds the lowest age among different ages:

// An array storing different ages
int ages[] = {20, 22, 18, 35, 48, 26, 87, 70};

// Get the length of the array
int length = sizeof(ages) / sizeof(ages[0]);

// Create a variable and assign the first array element of ages to it
int lowestAge = ages[0];

// Loop through the elements of the ages array to find the lowest age
for (int i = 0; i < length; i++) {
  if (lowestAge > ages[i]) {
    lowestAge = ages[i];
  }
}
Try it Yourself »

For a tutorial about arrays in C, visit our Arrays Chapter.


Strings

Example

Use strings to create a simple welcome message:

char message[] = "Good to see you,";
char fname[] = "John";

printf("%s %s!", message, fname);
Try it Yourself »

Example

Create a program that counts the number of characters found in a specific word:

char word[] = "Computer";
printf("The word '%s' has %d characters in it.", word, strlen(word));
Try it Yourself »

For a tutorial about strings in C, visit our Strings Chapter.


User Input

Example

Get the name of a user and print it:

char fullName[30];

printf("Type your full name: \n");
fgets(fullName, sizeof(fullName), stdin);

printf("Hello %s", fullName);
Run example »

For a tutorial about user input in C, visit our User Input Chapter.


Functions

Example

Use a function to create a program that converts a value from fahrenheit to celsius:

// Function to convert Fahrenheit to Celsius
float toCelsius(float fahrenheit) {
  return (5.0 / 9.0) * (fahrenheit - 32.0);
}

int main() {
  // Set a fahrenheit value
  float f_value = 98.8;

  // Call the function with the fahrenheit value
  float result = toCelsius(f_value);

  // Print the fahrenheit value
  printf("Fahrenheit: %.2f\n", f_value);

  // Print the result
  printf("Convert Fahrenheit to Celsius: %.2f\n", result);

  return 0;
}
Try it Yourself »

For a tutorial about functions in C, visit our Functions Chapter.


Structures

Example

Use a structure to store and output different information about Cars:

struct Car {
  char brand[50];
  char model[50];
  int year;
};

int main() {
  struct Car car1 = {"BMW", "X5", 1999};
  struct Car car2 = {"Ford", "Mustang", 1969};
  struct Car car3 = {"Toyota", "Corolla", 2011};

  printf("%s %s %d\n", car1.brand, car1.model, car1.year);
  printf("%s %s %d\n", car2.brand, car2.model, car2.year);
  printf("%s %s %d\n", car3.brand, car3.model, car3.year);

  return 0;
}
Try it Yourself »

For a tutorial about structures in C, visit our Structures Chapter.



×

Contact Sales

If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail:
sales@w3schools.com

Report Error

If you want to report an error, or if you want to make a suggestion, send us an e-mail:
help@w3schools.com

W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. While using W3Schools, you agree to have read and accepted our terms of use, cookie and privacy policy.

Copyright 1999-2024 by Refsnes Data. All Rights Reserved. W3Schools is Powered by W3.CSS.