Kurt Acosta Kurt Acosta - 4 months ago 17
Android Question

Is there a way to show the step by step computation of a calculation in Java?

I am currently building an Android app that has a calculator that not only shows the result, but also shows how it reached that result?

Is there any library or any way that I could show a step by step computation for the result of the code below?

int a = 5;
int b = 6
int c = 7;
int d = 8;

int result = a + (b * c) / d;


edit: By the way, it's a calculator for physics so I have lots of formulas. I'm using exp4j to parse a string formula as an expression. Here's a sample

//For formula velocity = (finalVelocity - initialVelocity) / time
String formula1 = "(finalVelocity - initialVelocity) / time";
Double result1 = new ExpressionBuilder(formula)
.variables("finalVelocity", "initialVelocity", "time")
.build()
.setVariable("finalVelocity", 4);
.setVariable("initialVelocity", 2);
.setVariable("time", 2)
.evaluate();
//Sample Output
//velocity = (4 - 2) / 2
//velocity = 2 /2
//velocity = 1

//For formula finalVelocity = (velocity * time) + initialVelocity
String formula2 = "(velocity * time) + initialVelocity";
Double result12 = new ExpressionBuilder(formula)
.variables("velocity", "time" "initialVelocity")
.build()
.setVariable("velocity", 4);
.setVariable("time", 2)
.setVariable("initialVelocity", 0)
.evaluate();
//Sample Output
//finalVelocity = (4 * 2) + 0
//finalVelocity = 8 + 0
//finalVelocity = 8


With many formulas, I'm trying to eliminate printing each step per formula. I'm trying to find a way to have a function that would print the steps for any formula.

Answer

Considering you will be using BODMAS to solve that problem, you could consider simply printing each step:

int a = 5;
int b = 6;
int c = 7;
int d = 8;
int ans = (b * c);
System.out.println(ans)
ans /= d;
System.out.println(ans)
ans += a;
System.out.println(ans)

To do this, you can build a function which searches for brackets first and solves the equations in the according to BODMAS(Brackets first, then Division, then Multiplication, then Addition, and finally Subtraction).
Considering you take the equation as a string, you first search for (), then solve / and print answers followed by *, + and -.