Difference between break and continue in C++

A loop control statement used to end a loop in C++ is called a break. The loop iterations end as soon as the break statement is met from inside the loop, and control is instantly transferred from the loop to the first statement after the loop.

Break statements are generally used when we are unsure of the precise number of loop iterations or when we wish to end the loop depending on a condition.

Here, we'll explore how to use three distinct loop types with break statements:

Simple loops
Nested loops
Infinite loops

Now let's examine the break statement-based examples for each of the three loop types mentioned above.

Break with Simple loops

Think about a scenario where we need to find a certain element in an array. Use a loop to iterate through the array starting at the first index, and then compare the array members with the provided key to do this.

Example:

// C++ program to illustrate
// Linear Search
#include <iostream>
using namespace std;
void findElement(int arr[], int size, int key)
{
	// loop to traverse array and search for key
	for (int i = 0; i < size; i++) {
		if (arr[i] == key) {
			cout << "Element found at position: " << (i + 1);
		}
	}
}
// Driver program to test above function
int main()
{
	int arr[] = { 1, 2, 3, 4, 5, 6 };
	int n = 6; // no of elements
	int key = 3; // key to be searched
	// Calling function to find the key
	findElement(arr, n, key);
	return 0;
}

OUTPUT:

Element found at position: 3
……………………………………………
Process executed in 1.11 seconds
Press any key to continue.

Explanation

The aforementioned code executes without a hitch. However the aforementioned code is ineffective. Even when the element is located, the aforementioned code still completes all iterations. If the array contains 1000 elements and the key to be searched is present in the first place, the aforementioned technique will run 999 unnecessary iterations.

We may utilize the break statement in our software to prevent these pointless iterations. The control from the loop returns as soon as the condition is met after the break statement is reached. Thus, as shown below, we will combine the break statement with the if condition that compares the key with array elements:

Example:

// C++ program to illustrate
// using break statement
// in Linear Search
#include <iostream>
using namespace std;
void findElement(int arr[], int size, int key)
{
	// loop to traverse array and search for key
	for (int i = 0; i < size; i++) {
		if (arr[i] == key) {
			cout << "Element found at position: "
				<< (i + 1);
			// using break to terminate loop execution
			break;
		}
	}
}
// Driver program to test above function
int main()
{
	int arr[] = { 1, 2, 3, 4, 5, 6 };
	// no of elements
	int n = 6;
	// key to be searched
	int key = 3;
	// Calling function to find the key
	findElement(arr, n, key);
	return 0;
}

OUTPUT:

Element found at position: 3
..................................................
Process executed in 1.11 seconds
Press any key to continue.

Break with Nested Loops

In working with nested loops, break statements are also an option if the innermost loop contains the break statement. Just the innermost loop will release the control.

// C++ program to illustrate
// using break statement
// in Nested loops
#include <iostream>
using namespace std;
int main()
{

	// nested for loops with break statement
	// at inner loop
	for (int i = 0; i < 5; i++) {
		for (int j = 1; j <= 10; j++) {
			if (j > 3)
				break;
			else
				cout << "*";
		}
		cout << endl;
	}
	return 0;
}

OUTPUT:

***
***
***
***
***
……………………..
Process executed in 1.11 seconds
Press any key to continue.

Explanation

We can see from the code above that the inner loop is set up to run for 10 iterations. Nevertheless, the inner loop ceases to run as soon as the value of j rises over 3, limiting the inner loop's iterations to just 3. The outer loop iteration, however, is unaffected. So, break only has an impact on the loop it is present in.

Break with Infinite Loops

For the purpose of ending the execution of an endless loop, the break statement can be used in conjunction with a condition.

Example:

// C++ program to illustrate
// using break statement
// in Infinite loops
#include <iostream>
using namespace std;
int main()
{
	// loop initialization expression
	int i = 0;
	// infinite while loop
	while (1) {
		cout << i << " ";
		i++;
	}
	return 0;
}

OUTPUT:

Execution timed out 
..................................
Process executed in 1.11 seconds
Press any key to continue.

Explanation

The loop condition in the aforementioned program, which determines when to end the loop, is always true. This causes the loop to run indefinitely.

NOTE: Please refrain from running the aforementioned program in your compiler since it is in an indefinite loop and will likely require you to forcibly quit the compiler in order to end the program.

By use the break statement, as seen below, we can fix this:

// C++ program to illustrate
// using break statement
// in Infinite loops
#include <iostream>
using namespace std;

int main()
{
	// loop initialization expression
	int i = 1;

	// infinite while loop
	while (1) {
		if (i > 10)
			break;

		cout << i << " ";
		i++;
	}

	return 0;
}

OUTPUT:

1 2 3 4 5 6 7 8 9 10 
................................
Process executed in 1.11 seconds
Press any key to continue.

Explanation

The aforementioned code limits the loop iterations to ten. Apart from this, Switch case statements can also employ the break.

Continue statement in C

The C languages continue statement acts as a jump statement to move program control to the beginning of the loop. The while loop, for loop, or do while loop all have a continue statement that we may use to change the way the program normally runs. It cannot be used with a C switch case, in contrast to break.

When used, the C continue statement returns program control to the loop's start. As a result, the control shifts to the following iteration of the loop and skips the current one. The statements in the loop that follow the continue statement are not carried out.

Just placing the continue keyword anywhere we wish in the loop body constitutes the continue syntax.

Use of continue in C

Each type of loop in C can skip the current iteration by using the continue statement. It may be applied to the following kinds of loops in C:

Single Loops
Nested Loops

Using continue in infinite loops is not useful as skipping the current iteration won't make a difference when the number of iterations is infinite.

Example of continue in C

Example 1: C A program that uses a single loop and the continue statement.

The for, while, and do-while loops all support the continue statement.

// C program to explain the use
// of continue statement with for loop

#include <stdio.h>

int main()
{
	// for loop to print 1 to 8
	for (int i = 1; i <= 8; i++) {
		// when i = 4, the iteration will be skipped and for
		// will not be printed
		if (i == 4) {
			continue;
		}
		printf("%d ", i);
	}
	printf("\n");

	int i = 0;
	// while loop to print 1 to 8
	while (i < 8) {
		// when i = 4, the iteration will be skipped and for
		// will not be printed
		i++;
		if (i == 4) {
			continue;
		}
		printf("%d ", i);
	}
	return 0;
}

OUTPUT:

1 2 3 5 6 7 8 
1 2 3 5 6 7 8 
.........................
Process executed in 1. 11 seconds
Press any key to continue.

Example 2: A program to utilize nested loops continues in C.

One loop at a time is all that the continue statement can handle. In order to skip the current iteration of the inner loop while utilizing nested loops, we may use the continue statement.

// C program to explain the use
// of continue statement with nested loops
#include <stdio.h>

int main()
{

	// outer loop with 3 iterations
	for (int i = 1; i <= 3; i++) {
		// inner loop to print integer 1 to 4
		for (int j = 0; j <= 4; j++) {

			// continue to skip printing number 3
			if (j == 3) {
				continue;
			}
			printf("%d ", j);
		}
		printf("\n");
	}
	return 0;
}

OUTPUT:

0 1 2 4 
0 1 2 4 
0 1 2 4 
.............
Process executed in 1.11 seconds
Press any key to continue.

Explanation

When the continue statement is used in the program above, it skips the current inner loop iteration. As a consequence, the inner loop update expression manages the program. 3 is never seen in the output in this fashion.

The continue statement operates as follows:

STEP 1: After determining that the loop condition is true, the loop begins to run.
STEP 2: The continue statement's condition will be assessed.
STEP 3A: If the condition is untrue, the execution will proceed as usual.
STEP 3B: If the condition is met, the program will move to the beginning of the loop and skip everything that comes after the continue statement.
STEP 4: Up until the loop's conclusion, steps 1 through 4 will be repeated.

Although while the statements used to expressly change the regular flow of a program break and continue are of the same kind, there are some differences between them.

With the break statement, the smallest enclosing loop is ended (i. e., while, do-while, for or switch statement)
Continue: The continue statement skips the remaining loop statements and starts the loop's subsequent iteration.

An illustration of the distinction between a break and continue statement.

// CPP program to demonstrate difference between
// continue and break
#include <iostream>
using namespace std;
main()
{
	int i;
	cout << "The loop with break produces output as: \n";

	for (i = 1; i <= 5; i++) {

		// Program comes out of loop when
		// i becomes multiple of 3.
		if ((i % 3) == 0)
			break;
		else
			cout << i << " ";
	}
	cout << "\nThe loop with continue produces output as: \n";
	for (i = 1; i <= 5; i++) {

		// The loop prints all values except
		// those that are multiple of 3.
		if ((i % 3) == 0)
			continue;
		cout << i << " ";
	}
}

OUTPUT:

The loop with break produces output as: 
1 2 
The loop with continue produces output as: 
1 2 4 5
……………………………………………………………………..
Process executed in 0.1 seconds
Press any key to continue.

Explanation:

Explanation: In the program above, the first loop would display the value of I up to 3 and then stop since a break statement was used when I equaled 3. And when i is equal to 3, the second for loop will continue running without printing the result of i.

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