基于ifstream，我使用以下函数读取filename.txt文件
//reading from text file
static std::vector<double> vec;
double a[18]; //values got read from txt file
int i = 0;
void readDATA()
{
double value;
std::ifstream myFile;
myFile.open("filename.txt", std::ios::app);
if (myFile.is_open())
{
std::cout << "File is open." << std::endl;
while (myFile >> value)
{
vec.push_back(value);
std::cout << "value is " << value << std::endl;
a[i] = value;
std::cout << "a" << i << "=" << a[i] << std::endl;
i = i + 1;
}
myFile.close();
}
else
std::cout << "Unable to open the file";
}
以下是filename.txt文件的内容:
0 0 40 45 15
0 1 40 -45 10
0 0 180 90 15
你能帮我修改一下这个函数吗？这样我就可以读取相同的。txt文件，其中的元素之间用逗号分隔？
你想读数字后跟冒号吗？
定义将处理此“任务”的类:
struct Number
{
double value;
operator double() const { return value; }
};
std::istream& operator >>(std::istream& is, Number& number)
{
is >> number.value;
// fail istream on anything other than ','
std::string dummy;
if (is >> dummy)
if (!(dummy.length() == 1) || !(dummy[0]==','))
is.setstate(std::ios_base::failbit);
return is;
}
然后在代码中-将double value；替换为number value；
你可以试试这样的东西
std::string data;
while(std::getline(myFile, data) {
std::istringstream ss(data);
std::string token;
while(std::getline(ss, token, ',')) {
double d = std::stod(token);
}
}
