将double转换成保留两位小数的string

string doubleToString(const double &dbNum)
{
    char *chCode;
    chCode = new(std::nothrow)char[20];
    sprintf(chCode, "%.2lf", dbNum);  // .2 是控制输出精度的，两位小数
    string strCode(chCode);
    delete []chCode;
    return strCode;
}
//调用方式
double dboule = 100.01555;
string str = doubleToString(dboule);
cout << str << endl;