This article was co-authored by Jake Adams. Jake Adams is an academic tutor and the owner of Simplifi EDU, a Santa Monica, California based online tutoring business offering learning resources and online tutors for academic subjects K-College, SAT & ACT prep, and college admissions applications. With over 14 years of professional tutoring experience, Jake is dedicated to providing his clients the very best online tutoring experience and access to a network of excellent undergraduate and graduate-level tutors from top colleges all over the nation. Jake holds a BS in International Business and Marketing from Pepperdine University.
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Calculating percentage can be of great help. But when the numbers get bigger, using a program to calculate it becomes much easier. Here is how you can create a program to calculate percentage, in Java.
Steps
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1Plan your program. Though calculating percentage isn't difficult, it is always a good practice to plan your program before beginning to code. Try finding the answers of the following questions:
- Is your program going to handle large numbers? If yes, then try thinking about ways in which your program can handle large range of numbers. One way of doing this is using a float or long variable instead of int.
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2Write the code. To calculate percentage, you will need two parameters:
- The total score (or the maximum possible score); and,
- The obtained score whose percentage you wish to calculate.
- For example: If a student scores 30 marks out of 100 in a test, and you wish to calculate the percentage marks scored by the student, 100 is the total marks (or the maximum possible score). 30 is the obtained score whose percentage you wish to calculate.
- The formula to calculate percentage is:
Percentage = (Obtained score x 100) / Total Score - To get these parameters (inputs) from the user, try using the Scanner function in Java.
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3Calculate the percentage. Use the formula given in the previous step to calculate the percentage. Make sure that the variable used for storing the value of percentage is of type float. If not, the answer may not be correct.
- This is because, the float data-type is 32 bit single precision that even considers decimals in mathematical calculations. Thus, using a float variable, the answer for a mathematical calculation like 5 / 2 (5 divided by 2) will be 2.5
- If the same calculation (5 / 2) if done using an int variable, the answer will be 2.
- However, the variables in which you stored the total score and obtained score can be int. Using a float variable for the percentage will automatically convert the int to float; and the total calculation will be done in float instead of int.
- This is because, the float data-type is 32 bit single precision that even considers decimals in mathematical calculations. Thus, using a float variable, the answer for a mathematical calculation like 5 / 2 (5 divided by 2) will be 2.5
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4Display the percentage to the user. Once the program has calculated the percentage, display it to the user. Use the System.out.print or System.out.println (to print on a new line) function, in Java, for this.
Sample Code
import java.util.Scanner;
public class main_class {
public static void main(String[] args){
int total, score;
float percentage;
Scanner inputNumScanner = new Scanner(System.in);
System.out.println("Enter the total, or max, score: ");
total = inputNumScanner.nextInt();
System.out.println("Enter the score obtained: ");
score = inputNumScanner.nextInt();
percentage = (score * 100/ total);
System.out.println("The percentage is = " + percentage + " %");
}
}
Community Q&A
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QuestionHow do I write 5.365 as a percentage?Community Answer536.5% (original number times 100).
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QuestionShould I use float instead to find percentages? (It's for an exam.)Community AnswerIt really depends on the application. A float variable will give you more precise values with decimals, and an int variable will give you rounded whole numbers.
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QuestionHow do I get decimal points instead of zero?Community AnswerYou use a float or double instead of int. A double is more accurate, but you won't necessarily use that more than a float.