C++ for Loop

Introduction to C++ – A Comprehensive Course for Beginners C++ for Loop

In this lesson, we will introduce loop statements, particularly the C++ ‘for loop,’ with a few examples.

Looping Statement

Loops are used in computer programming to run a block of code repeatedly. Let’s imagine, for illustration, that we wish to display a message 100 times. Then we can utilize a loop rather than writing the print statement 100 times. That was just a simple illustration; using loops effectively can make our program considerably more efficient.

C++ offers three different types of loops:

C++ For loop
C++ while loop
C++ do while loop

This lesson’s primary emphasis is C++ “for loop”. In future lessons, we will learn about the additional types of loops.

C++ For Loop

Basic syntax

for (initialization; condition; increment/decrement) {
// body
}

Here, in the above syntax of for loop

Initialization initializes variables and is only performed once condition.
If true, the loop’s” body is executed.
If false, the loop ends.
Increment/Decrement initialized variables’ values while once again examining the condition.

Example

//Program prints 3 integers
#include <iostream>

using namespace std;
int main() {
  int number;
  for (number = 3; number >= 1; number--) {
    cout << number << " ";
  }
  return 0;
}

Output

3 2 1

That’s how the program performs

Variant	Variable Update	number >= 1	Action
1st	number = 3	True	3 is printed. The number is decreased to 3.
2nd	number = 2	True	2 is printed. The number is decreased to 2.
3rd	number = 1	True	One is printed. The number is decreased to 1.
4th	number = 0	False	Program terminated

Ranged Based for Loop

A new range-based for loop was added in C++11 to support working with collections like arrays and vectors. The basic syntax is below:

Basic Syntax

for (variable: collection) {
// body of the sloop
}

In this case, the ‘for loop’ executes for every collection item, and the value is then assigned to the variable.

Example

//Program prints 5 integers
#include <iostream>

using namespace std;
int main() {
  int numberArray[] = {
    100,
    200,
    300,
    400,
    500
  };
  for (int number: numberArray) {
    cout << number << " ";
  }
  return 0;
}

Output

100 200 300 400 500

An int array named numberArray has been declared and initialized in the program above. Here, a range-based for loop is utilized to access every array element. Five numbers will be printed.

This concludes the C++ for loop lesson. The next lesson will learn about the “while loop” in C++.

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