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el.trasgu
Asked: 2022-08-01 19:45:43 +0800 CST 2022-08-01 19:45:43 +0800 CST

Correct calculation of percentages in java

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A few days ago a community user asked this question, and once I answered it, he decided to delete it.

Since it had taken me some time to craft the answer to get the code to work, I'm taking the liberty of reposting the question and my answer.

The question was the following:

Good day. Could someone please help me with this error, I have to get a percentage from a range of numbers. I get the count correctly, but the arithmetic doesn't work for me to get the percentage.

public class Ej08 {
    public static void main(String[] args) throws Exception {
       int n;
       int suma=0;
       int bajo=0;
       int inv=0;
       float num;
       double mbajo= 5.0;
       float mybajo= 14;
       double minv= 80.0;
       float myinv= 100;
       int i;
       java.util.Scanner lea = new java.util.Scanner(System.in);
       System.out.print("Indique la cantidad de numeros : ");
       n = lea.nextInt();
       if(n<=0)
           System.out.println("El valor no es valido");
       else {
           for(i=1;i<=n;i++) {
               System.out.print("Dato "+i+" : ");
               num=lea.nextFloat();
               suma += num;
               if(num> mbajo && num<=mybajo){
                   bajo= bajo + 1;
                   System.out.println(" sumo "+ num);

               }
               if(num> minv && num <= myinv){
                   inv= inv + 1;
                   System.out.println(" sumo "+ num);
                
               }
           }
           System.out.println("bajo trae: "+bajo);
           System.out.println("inviable tre: "+inv);
           System.out.println("n trae: "+n);
           double prom= (suma/(n*1.0));
           float pb=(bajo /n)*100;
           float pi=(inv / n)*100;
        
           /* if (prom>=01){
               5.1 7 25 70 50 90
           }*/
        
           System.out.println("El promedio de los números es : "+prom);
           System.out.println("bajo: "+pb);
           System.out.println("inviable: "+pi);
       }
       lea.close();

In the code you can see that the low variable brings 2 and the inv variable brings 1 and the n variable brings 6 which is the number of times the program reads.

I need to know how much is under n, that is, how much is 2 of 6 is simple, it is divided and multiplied by 100, but it does not perform the operation because in the end pb and pi have 0.0 as a result

java

1 Answers

  1. Best Answer

    Let's see if I found out what you need and I'll give you a good answer

    The low numbers are those between 6 and 14

    The unfeasible numbers, those between 81 and 100

    Every time you enter a number on the keyboard that falls between the previous parameters, you increase their respective counters.

    public static void main(String[] args) throws Exception {
    //declaramos las variables de enteros
    int n, suma = 0, bajo = 0, inv = 0;
    //el resto de variables como las tienes declaradas
    float num;
    double mbajo = 5.0;
    float mybajo = 14;
    double minv = 80.0;
    float myinv = 100;
    //instalaciones la clase escaner
    java.util.Scanner lea = new java.util.Scanner(System.in);
    //pedimos la cantadiad de números por consola
    System.out.print("Indique la cantidad de numeros : ");
    //recogemos los números en la variable n
    n = lea.nextInt();
    //si n menor o igual a 0
    if (n <= 0)
        //informamos de la invalidez del número
        System.out.println("El valor no es valido");
    //si es válido
    else {
        //declaramos un bucle limitado por el número de números dado
        for(int i = 1; i <= n; i++) {
            //vamos pidiendo los números
            System.out.print("Dato " + i + " : ");
            //guardamos el número dado en la variable num decimal
            num = lea.nextFloat();
            //acumulamos la suma de los números que se van dando en la variable suma
            suma += num;
            //si el número está por encima del mínimo bajo y es igual o está por debajo del máximo mínimo
            if(num > mbajo && num <= mybajo){
                //sumamos 1 a bajo
                bajo += 1;
                //System.out.println(" sumo " + num);
            }
            //si num está por encima del mínimo inviable o es igual o está por debajo del máximo inviable
            if(num > minv && num <= myinv){
                //sumamos uno al la variable inviable
                inv += 1;
                //System.out.println(" sumo " + num);
            
            }
        }
        //mostramos los resultados de bajo, inv y n
        System.out.println("bajo trae: " + bajo);
        System.out.println("inviable trae: " + inv);
        System.out.println("n trae: " + n);
    
        //hayamos los porcentajes de los promedios
        double prom = (suma / n);
        float pb = (bajo * 100) / n;
        float pi = (inv * 100) / n;
    
       /* if (prom>=01){
            5.1 7 25 70 50 90
        }*/
    
        //mostramos el resultado de los promedios
        System.out.println("El promedio de los números es : " + prom);
        System.out.println("bajo: " + pb);
        System.out.println("inviable: " + pi);
    }
    //derramos el teclado
    lea.close();
}
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