Why does this math function return different values in Java and JavaScript?

Question

This JavaScript code returns 115.3:

function FV(rate, nper, pmt, pv, type) {
    var pow = Math.pow(1 + rate, nper);
    var fv;
    if (rate) {
        fv = (pmt*(1+rate*type)*(1-pow)/rate)-pv*pow;
    } else {
        fv = -1 * (pv + pmt * nper);
    }
    return fv.toFixed(2);
}

document.write(   FV(0.06/12,12,-(2750+1375)/12,-0,0)-(0+2750+1375)    )

This Java code returns 106.1:

public double FV(double rate, double nper, double pmt, double pv, int type) {
    double pow = Math.pow(1 + rate, nper);
    double fv;        
    if (rate > 0) {
        fv = (pmt*(1+rate*type)*(1-pow)/rate)-pv*pow;
    } else {
        fv = -1 * (pv + pmt * nper);
    }
    return fv;
}
System.out.println(FV(0.06/12,12,-(2750+1375)/12,-0,0)-(0+2750+1375));

They look the same to me, but they return different values. What's wrong?

Default type of Java integer literals int and int devision round up the value. whereas in javascript devision operator return value dynamically, ex. 1 / 2 // returns 0.5 in JavaScript and 1 / 2 // returns 0 in Java — Subhrajyoti Majumder
– Subhrajyoti Majumder, Commented May 7, 2015 at 17:01
@SubhrajyotiMajumder Integer division rounds towards zero. The JLS says this about it: Integer division rounds toward 0. That is, the quotient produced for operands n and d that are integers after binary numeric promotion (§5.6.2) is an integer value q whose magnitude is as large as possible while satisfying |d · q| ≤ |n|. Moreover, q is positive when |n| ≥ |d| and n and d have the same sign, but q is negative when |n| ≥ |d| and n and d have opposite signs. — mkobit
– mkobit, Commented Jul 8, 2015 at 18:07

Tagir Valeev · Accepted Answer · 2015-05-07 16:49:23Z

26

In JavaScript -(2750+1375)/12 evaluates to -343.75. In Java it evaluates to -343, because in Java when you divide integer numbers, you get integer result. To fix this simply replace the expression with -(2750+1375)/12.0.

answered May 7, 2015 at 16:49

Tagir Valeev

101k19 gold badges233 silver badges346 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Why does this math function return different values in Java and JavaScript?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related