Mathematical equation with mixed data types in java

Question

I've been given a problem to calculate the number of years(nbYear) it would take for a population(p0) to rise or decrease to a certain number of people(p) if the population would increas/decrease by precentage(percent) and additional people(aug) a year.

public static int nbYear(int p0, double percent, int aug, int p) {
    int nbYear = 0;
    while(p0 < p){
      p0 = p0 + (p0 * percent) + aug;
      nbYear = nbYear + 1;
    } 
    return nbYear;
}

}

This code would be ok but I get a possible lossy conversion from double to int error. My question is how can you calculate a mathematical equation with mixed data types in (this case int and double) without any information loss?

Any help is much appreciated!

Answer 1

You cannot assign a double value to an int variable without explicitly handling the data loss. One way to do this is to explicitly use a narrowing cast to int, under the assumption that a population cannot increase by a part of a person:

p0 = p0 + (int)(p0 * percent) + aug;
// Here --^