Js floating point operation BUG solution

  • 2020-03-30 01:12:48
  • OfStack

I used it in a project where I found this code on the web, but under certain conditions there were still bugs in division and addition and I personally optimized it a little bit


//Division function, used to get accurate division results
//Note: javascript division results will have errors, in two floating point division will be more obvious. This function returns a more precise division result.
//Call: accDiv (arg1, arg2)
//Return value: the exact result of arg1 divided by arg2
function accDiv(arg1, arg2) {
    var t1 = 0, t2 = 0, r1, r2;
    try { t1 = arg1.toString().split(".")[1].length } catch (e) { }
    try { t2 = arg2.toString().split(".")[1].length } catch (e) { }
    with (Math) {
        r1 = Number(arg1.toString().replace(".", ""))
        r2 = Number(arg2.toString().replace(".", ""))
        return accMul((r1 / r2),pow(10, t2 - t1));
    }
} 


//The multiplication function, which is used to get exact multiplication results
//Note: javascript multiplication results will have errors, in the two floating point number multiplication will be more obvious. This function returns a more precise multiplication result.
//Call: accMul (arg1, arg2)
//Return value: the exact result of arg1 times arg2
function accMul(arg1, arg2) {
    var m = 0, s1 = arg1.toString(), s2 = arg2.toString();
    try { m += s1.split(".")[1].length } catch (e) { }
    try { m += s2.split(".")[1].length } catch (e) { }
    return Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m)
} 


//Intermediate solution for addition
function accAdd(arg1, arg2) {   
    var r1, r2, m, c;
    try { r1 = arg1.toString().split(".")[1].length } catch (e) { r1 = 0 }
    try { r2 = arg2.toString().split(".")[1].length } catch (e) { r2 = 0 }  
    c = Math.abs(r1 - r2);   
    m = Math.pow(10, Math.max(r1, r2))   
    if (c > 0) {   
        var cm = Math.pow(10, c);   
        if (r1 > r2) {   
            arg1 = Number(arg1.toString().replace(".", ""));   
            arg2 = Number(arg2.toString().replace(".", "")) * cm;   
        }   
        else {   
            arg1 = Number(arg1.toString().replace(".", "")) * cm;   
            arg2 = Number(arg2.toString().replace(".", ""));   
        }   
    }   
    else {   
        arg1 = Number(arg1.toString().replace(".", ""));   
        arg2 = Number(arg2.toString().replace(".", ""));   
    }   
    return accDiv((arg1 + arg2),m); 
} 


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