You have already seen the break statement used in an earlier chapter of this tutorial. It was used to “jump out” of a switch statement.
The break statement can also be used to jump out of a loop.
This example jumps out of the loop when i is equal to 4:
for (int i = 0; i < 10; i++) {
if (i == 4) {
break;
}
cout << i << "\n";
}
To demonstrate a practical example of the for loop, let’s create a program that counts to 100 by tens:
for (int i = 0; i <= 100; i += 10) {
cout << i << "\n";
}
In this example, we create a program that only print even numbers between 0 and 10 (inclusive): Continue reading C++ For Loop Examples
There is also a “for-each loop” (also known as ranged-based for loop), which is used exclusively to loop through elements in an array (or other data structures):
for (type variableName : arrayName) {
// code block to be executed
}
The following example outputs all elements in an array, using a “for-each loop”: Continue reading C++ The foreach Loop
It is also possible to place a loop inside another loop. This is called a nested loop.
The “inner loop” will be executed one time for each iteration of the “outer loop”:
// Outer loop
for (int i = 1; i <= 2; ++i) {
cout << "Outer: " << i << "\n"; // Executes 2 times
// Inner loop
for (int j = 1; j <= 3; ++j) {
cout << " Inner: " << j << "\n"; // Executes 6 times (2 * 3)
}
}
When you know exactly how many times you want to loop through a block of code, use the for loop instead of a while loop:
for (statement 1; statement 2; statement 3) {
// code block to be executed
}
Statement 1 is executed (one time) before the execution of the code block.
Statement 2 defines the condition for executing the code block.
Statement 3 is executed (every time) after the code block has been executed. Continue reading C++ For Loop
To demonstrate a practical example of the while loop, we have created a simple “countdown” program:
int countdown = 3;
while (countdown > 0) {
cout << countdown << "\n";
countdown--;
}
cout << "Happy New Year!!\n";
In this example, we create a program that only print even numbers between 0 and 10 (inclusive): Continue reading C++ While Loop Examples
The do/while loop is a variant of the while loop. This loop will execute the code block once, before checking if the condition is true, then it will repeat the loop as long as the condition is true. Continue reading C++ Do/While Loop
Loops can execute a block of code as long as a specified condition is reached.
Loops are handy because they save time, reduce errors, and they make code more readable.
Use the switch statement to select one of many code blocks to be executed.
switch(expression) {
case x:
// code block
break;
case y:
// code block
break;
default:
// code block
}
This is how it works:
switch expression is evaluated oncecasebreak and default keywords are optional, and will be described later in this chapterThe example below uses the weekday number to calculate the weekday name: Continue reading C++ Switch
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) {
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 : Continue reading C++ If … Else Examples