What are loops?
A loop can execute a set of statements again and again until a certain condition is reached.
Example 1:
If a teacher asked a student to demonstrate the counting from 1 to 10. Then he can ask the student to demonstrate the counting by two different methods.
Method 1:
A teacher can ask the student to demonstrate the counting from 1,2,3,4,5,6,7,8,9 to 10.
- Method 2:
The teacher can ask the student to demonstrate the counting from 1 to 10.
Think about it, which one method is best?
Exactly it is better if we used the second method. The concept of the loop is similar to this.
What is a mechanism of the loop?
When we try to run a loop, then we have to care for the followings;
- Loop initialization
- Loop Condition
- Loop Increment/Decrement
What is Loop initialization?
For example: In the example above the beginning of loop is from 1
What is Loop Condition?
Allows the loop to execute only when the condition is true.
For example: In the example above the termination of loop occurred at 10.
What is Loop Increment/Decrement?
For example: In example 6.1, loop increment is the increment from 1 to 2, from 2 to 3, from 3 to 4, from 4 to 5, from 5 to 6, from 6 to 7, from 7 to 8, from 8 to 9 and from 9 to 10.
After reaching to 10 what the student do?
Exactly the student stops at 10 because there is a condition to terminate the loop at 10.
Now let’s begin with a programming example.
Example 2:
If we want to print hello 5 times on the screen without a loop, then we can write the code as follows
| Line No | Program Code |
| 1 | cout<<”loop is working”; |
| 2 | cout<<”loop is working”; |
| 3 | cout<<”loop is working”; |
| 4 | cout<<”loop is working”; |
| 5 | cout<<”loop is working”; |
Example: Statements without loop
If we take a little attention to this code, we can observe that we need to write the
| cout<<”loop is working”; |
five times again and again in the program. It is time-consuming. It also consumes more memory.
So there is a need to introduce a method that that can save a programmer time and can also save the computer memory.
Solution to this problem is by using a loop. Later we will discuss the solution in the example in next tutorial.
There are three common types of loops;
- For loop
- While loop
- Do While loop
| Test Your Understandings |
1.Loops execute again and again so occupies more space and consumes more time for the programmer?
YES / NO
2……………Used to stop the loop?
A- Loop initialization
B- Loop condition
C- Loop increment
D- All above.