How to Write a Loop to Read Positive Integers in Computer Programming -Comprehensive Guide

In this guide, we'll discuss how to write a loop to read positive integers in computer programming. Programming and understanding loops can be an integral part of computer science, but with the proper guidance and practice, anyone can become an expert. Loops are an efficient way to read a certain number of inputs from a user, repetitively execute a certain calculation, and continue a certain action until a certain condition is satisfied. With this guide, you’ll see how to construct a loop and code it to read positive integers.

What is a Loop?

A loop is a repeating set of commands that is a fundamental building block in programming. It takes a set of code and runs it multiple times until it meets the criteria called for in the loop. Loops can be used to read inputs, repeat an action, or run a calculation.

What are the Different Loops Used?

There are several types of loops that are used in programming. These include:

  • For Loop: A “for loop” is used to execute a set of code a specified number of times.
  • While Loop: A “while loop” runs a set of code until the condition of the loop is satisfied.
  • Do-While Loop: A “do-while loop” is similar to a “while loop”, however it executes at least once and then continues running until the condition is no longer true.

How to Write a Loop to Read Positive Integers

To loop to read positive integers, you'll need to use a “while loop” or a “do-while loop” and use an if-else statement within the loop. Here’s the basic structure of these loops:

While Loop

    // code block to be executed 

Do-While Loop

do { 
    // code block to be executed 

} while (condition); 

The condition within both types of loops must evaluate to true or false in order for the loop to operate correctly. The code block is the code that will be executed each time the loop runs.

To read positive integers specifically, you would insert an if-else statement within the loop. This statement will check whether the calculated number is a positive integer or not. If it is a positive integer, then the code will run, and if not, it will loop until it receives a positive integer. Here’s the code that you’ll need to use for this task:

while (true) {
  int number = calculatePositiveInteger(); 
  if (number >= 0 ) { 
    //write code to save positive number

First, the loop is initialized. This is done by using the keyword while and setting the condition to true. This will cause the loop to continue running until break is used. The integer is then calculated by the calculatePositiveInteger() that the user has defined. This is followed by the if statement. This is used to check whether the calculated integer is larger than 0 or not. If it is, then the code will run and the integer will be saved, and if not, the loop will continue running until a positive integer is found. Finally, the keyword break is used to end the loop once a positive integer is found.


What do “if-else” control statements do?

The “if-else” control statement is a conditional statement that enables a program to make decisions based on certain conditions. It evaluates the expressions and executes one condition or the other depending on the result of the condition.

What is the difference between a “for loop” and a “while loop”?

The main difference between a for loop and a while loop is that a for loop is used for iterating through an array, whereas a while loop is used for executing a certain set of code until the condition of the loop is satisfied.

What does the break keyword do?

The break keyword is used to end the execution of a loop when a certain condition is met.

What does the continue keyword do?

The continue keyword is used to continue the execution of a loop instead of executing the rest of the code in that loop iteration.

What is the purpose of using a loop to read positive integers?

Using a loop to read positive integers is a great way to make sure that a program is only executing code on a user’s input that is a positive integer. It eliminates any invalid inputs and keeps the program running efficiently.


This guide has discussed the basics of writing a loop to read positive integers in computer programming. We discussed what a loop is, the different types of loops, and how to write a loop using an “if-else” statement. We also included a FAQ section so you have a quick reference guide if there’s any additional information you need. With this guidance, you should be able to construct and code your own loop to read positive integers.

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