Various kind of loops in programming

Loops are the important part of the programming. It uses to perform any repetitive task then the loop is the best solution. It's a programming function that iterates a statement or condition based on specified boundaries.

A specific statement or a group of instructions is continuously executed until a specific loop body or boundary condition is reached. The result of the entire loop body’s first operation cycle serves as the next repetition’s starting point. The loop function uses almost identical logic and syntax in all programming languages.

If you can recognize the variations and their usability, then programming will become much easier for you. All loops have a basic structure and content with the variable that will control loop running times.

The number of the statements will be executed from initial stage until the condition is true or the other way says it repeating the statements until the given condition is not to be false. Every programming language includes the concept of a loop.

A loop is divided into two parts -

Loop Statement - This defines the time limit to be true for the continuous loop that is contingent on the attached conditional statement.

Loop Body - This holds the statement’s code or instruction; it is is executed with each loop cycle.

 

A computer programmer who needs to use the same lines of code many times in a program can use a loop to save time. There are only a few basic formats that are used repeatedly task to execution of the statements. Those are -

While loop

It also is known as the entry controlled loop that means the condition is checked at the start of the loop body. Loop body is not executed in false condition. If the condition is true then it will execute the statements and then it increases or decrease the value of a condition variable. So, you will have to be sure that the condition must be true. Because of that, it is not used for making menu driven programs.

while(condition) {
    statements;
}

Do while loop

It also is known as exit controlled loop which refers the condition is checked at the end of the loop body. The condition is true or not it executes the statements at least once. It increases/decrease the variable value and checks the condition. It supports to making menu driven programs.

do {
    statements;
} while(condition);

For loop

This loop support basic operations like initialization, condition checking and incrementing or decrementing all these are performed in only one line. This is also similar to the while loop for performing to the execution of statements at first level, but it is different in its syntax. It used to determine the time of the program that indicates how many times the loop will repeat. This is not always possible. There are generally two ways that the number of repetitions of a loop will know ahead of time such as the loop always repeats the same number of times and the program calculates the number of repetitions based upon user input.

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

Foreach loop

Foreach provides an easy way to iterate over arrays. It only works for arrays and objects, and when we try to use it on a variable with a different data type or an uninitialized variable it shows an error. Two common places for using this loop such as reading an unknown amount of input and validate the input. It makes simpler code to maintain no explicit counter and avoids potential off-by-one errors.

foreach(array_expression as value) {
    statements;
}

Infinite loop

An infinite or endless loop is a loop that repeats indefinitely because it has no terminating condition, the exit condition is never met or the loop is instructed to start over from the beginning. Although it is possible for a programmer to intentionally use an infinite loop, they are often mistakes made by new programmers.

Nested loop

A nested loop appears inside any other for, while or do-while loop. It's any type of loop inside an already existing loop. They can involve any type of loop.

Count Loops

The only time to use a count loop is when the program can determine ahead of time how many times the loop will repeat. This is not always possible. There are generally two ways that the number of repetitions of a loop will know ahead of time - The loop always repeats the same number of times, and the program calculates the number of repetitions based upon user input.

Do-Until loop

It iterates while a specified condition is TRUE. The condition is tested at the end of each iteration.