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
cout << "Student ID: " << studentID << "\n";
cout << "Student
Age: " << studentAge << "\n";
cout << "Student Fee: " << studentFee <<
"\n";
cout << "Student Grade: " << studentGrade << "\n";
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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
cout << "Length is: " << length << "\n";
cout << "Width is: " << width << "\n";
cout << "Area of the
rectangle is: " << area << "\n";
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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;
double
cost_per_item = 9.99;
double total_cost = items * cost_per_item;
char
currency = '$';
// Print variables
cout << "Number of items: " <<
items << "\n";
cout << "Cost per item: " << cost_per_item << "" <<
currency << "\n";
cout << "Total cost = " << total_cost << "" << currency
<< "\n";
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For a tutorial about variables and data types in C++, visit our Variables Chapter and Data Types Chapter.
Strings
Example
Use strings to create a simple welcome message:
string message = "Good to see you, ";
string fname = "John";
cout <<
greeting + fname;
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For a tutorial about strings in C++, visit our Strings Chapter.
Booleans
Example
Find out if a person is old enough to vote:
int myAge = 25;
int votingAge = 18;
cout << (myAge >= votingAge);
// returns 1 (true), meaning 25 year olds are allowed to vote!
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For a tutorial about booleans in C++, visit our Booleans Chapter.
Conditions (If..Else)
Example
Check whether the user enters the correct code:
int doorCode = 1337;
if (doorCode == 1337) {
cout << "Correct
code.\nThe door is now open.\n";
} else {
cout << "Wrong
code.\nThe door remains closed.\n";
}
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Example
Find out if a number is positive or negative:
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";
}
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Example
Find out if a person is old enough to vote:
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";
}
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Example
Find out if a number is even or odd:
int myNum = 5;
if (myNum % 2 == 0) {
cout << myNum << " is
even.\n";
} else {
cout << myNum << " is odd.\n";
}
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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:
cout << "Monday";
break;
case 2:
cout << "Tuesday";
break;
case 3:
cout << "Wednesday";
break;
case
4:
cout << "Thursday";
break;
case 5:
cout << "Friday";
break;
case 6:
cout << "Saturday";
break;
case 7:
cout << "Sunday";
break;
}
// Outputs "Thursday" (day 4)
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For a tutorial about switch in C++, visit our Switch Chapter.
While Loops
Example
Create a simple "countdown" program:
int countdown = 3;
while (countdown > 0) {
cout << countdown
<< "\n";
countdown--;
}
cout << "Happy New Year!!\n";
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Example
Create a program that only print even numbers between 0 and 10 (inclusive):
int i = 0;
while (i <= 10) {
cout << i << "\n";
i
+= 2;
}
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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 'revNumbers'
revNumbers = revNumbers * 10
+ numbers % 10;
// Remove the last number of 'numbers'
numbers /= 10;
}
cout << "Reversed numbers: " << revNumbers << "\n";
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Example
Use a while loop together with an if else statement to play a game of Yatzy:
int dice = 1;
while (dice <= 6) {
if (dice < 6) {
cout << "No Yatzy\n";
} else {
cout <<
"Yatzy!\n";
}
dice = dice + 1;
}
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For a tutorial about while loops in C++, visit our While Loops Chapter.
For Loops
Example
Use a for loop to create a program that counts to 100 by tens:
for (int i = 0; i <= 100; i += 10) {
cout << i << "\n";
}
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Example
Use a for loop to create a program that only print even values between 0 and 10:
for (int i = 0; i <= 10; i = i + 2) {
cout << i << "\n";
}
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Example
Use a for loop to create a program that only prints odd numbers:
for (int i = 1; i <= 10; i = i + 2) {
cout << i << "\n";
}
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Example
Use a for loop to print the powers of 2 up to 512:
for (int i = 2; i <= 512; i *= 2) {
cout << i << "\n";
}
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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++) {
cout << number << " x " << i
<< " = " << number * i << "\n";
}
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For a tutorial about for loops in C++, visit our For Loops Chapter.
Arrays
Example
Create a program that calculates the average of different ages:
// An array storing different ages
int ages[8] = {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 age : ages) {
sum += age;
}
// Calculate the average by dividing the sum by the length
avg = sum /
length;
// Print the average
cout << "The average age is: " << avg
<< "\n";
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Example
Create a program that finds the lowest age among different ages:
// An array storing different ages
int ages[8] = {20, 22, 18, 35, 48, 26,
87, 70};
int i;
// 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 age
: ages) {
if (lowestAge > age) {
lowestAge =
age;
}
}
// Print the lowest age
cout << "The lowest
age is: " << lowestAge << "\n";
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For a tutorial about arrays in C++, visit our Arrays Chapter.
Structs
Example
Use a structure to store and output different information about Cars:
// Declare a structure named "car"
struct car {
string brand;
string model;
int year;
};
int main() {
// Create a car structure and store it in myCar1;
car myCar1;
myCar1.brand = "BMW";
myCar1.model = "X5";
myCar1.year = 1999;
// Create another car structure and store it in myCar2;
car myCar2;
myCar2.brand = "Ford";
myCar2.model = "Mustang";
myCar2.year = 1969;
// Print the structure members
cout << myCar1.brand << " " << myCar1.model << " " << myCar1.year << "\n";
cout << myCar2.brand << " " << myCar2.model << " " << myCar2.year << "\n";
return 0;
}
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For a tutorial about structs in C++, visit our Structures Chapter.
Functions
Example
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
cout
<< "Fahrenheit: " << f_value << "\n";
// Print the result
cout << "Convert Fahrenheit to Celsius: " << result << "\n";
return 0;
}
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For a tutorial about functions in C++, visit our Functions Chapter.
