jsの計算精度の問題点まとめ_javascriptスキル

コードをコピー コードは次のとおりです:

//问题比如：7*0.8 JavaScript算出来就是：5.6000000000000005

            //加法函数，用来得到精确的加法结果
            //说明：javascript的加法结果会有误差，在两个浮点数相加的时候会比较明显。这个函数返回较为精确的加法结果。
            //调用：accAdd(arg1,arg2)
            //返回值：arg1加上arg2的精确结果
            function accAdd(arg1, arg2) {
                var r1, r2, m;
                try { r1 = arg1.toString().split(".")[1].length } catch (e) { r1 = 0 }
                try { r2 = arg2.toString().split(".")[1].length } catch (e) { r2 = 0 }
                m = Math.pow(10, Math.max(r1, r2))
                return (arg1 * m + arg2 * m) / m
            }
            //用法：
            //给Number类型增加一个add方法，调用起来更加方便。
            Number.prototype.add = function (arg) {
                return accAdd(arg, this);
            }
            //如：
            var t1 = 6.60;
            var t2 = 1.32;
            var t3 = 1.2;
            var t4 = 1.2;
            var t5 = 1.2;
            alert(Number(t1).add(Number(t2)).add(Number(t3)).add(Number(t4)).add(Number(t5)));

            //减法函数，用来得到精确的减法结果
            function Subtr(arg1, arg2) {
                var r1, r2, m, n;
                try { r1 = arg1.toString().split(".")[1].length } catch (e) { r1 = 0 }
                try { r2 = arg2.toString().split(".")[1].length } catch (e) { r2 = 0 }
                m = Math.pow(10, Math.max(r1, r2));
                //last modify by deeka
                //动态控制精度长度
                n = (r1 >= r2) ? r1 : r2;
                return ((arg1 * m - arg2 * m) / m).toFixed(n);
            }

// multiplication function is used to obtain accurate multiplication results
// Description: The multiplication results of JavaScript will have an error, and it will be obvious when the two floating -point numbers are multiplied. This function returns a more accurate multiplication result.
                                                                                                                                              0, s1 = arg1 .toString(), s2 = arg2.toString();
                      try { m = s1.split(".")[1].length } catch (e) {                         (".")[1].length } catch (e) { }
                                                                           return Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m)
                                                                                                                                                                                    .
Number.prototype.mul = function (arg) {
return accMul(arg, this);
}

// removal function is used to obtain accurate removal results
// explanation: The division results of JavaScript will have an error, and it will be obvious when the two floating -point numbers are removed. This function returns a more accurate division result.
                                                                                                                                           1 = 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) {

>               r2 = Number(arg2.toString().replace(".", ""))
                                                                                                                                                  >          }
// Usage: > // Add a DIV method to Number type, which is more convenient to call.