// 运算类

// 整合运算函数
function getMax(operation, arg1, arg2){
    var res = '';

    switch(operation)
    {
        case '+':
        res = accAdd(arg1, arg2);
        break;
        case '-':
        res = accSubtr(arg1, arg2);
        break;
        case '*':
        res = accMul(arg1, arg2);
        break;
        case '/':
        res = accDiv(arg1, arg2);
        break;
    }

    return res;
}


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;
}

function accSubtr(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));
    //动态控制精度长度
    n = (r1 >= r2) ? r1 : r2;
    return ((arg1 * m - arg2 * m) / m).toFixed(n);
}

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);
}

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 (r1 / r2) * pow(10, t2 - t1);
    }
}