I am sorry for my questions , they may be so silly
Ok, I read the line with get line, and I assigned that line to istringstream.
Code:
ifstream ccinp;
string line;
double number;
vector<double> cc;
while(getline(ccinp,line)){
cc.clear();
istringstream terr(line);
for(int i=0;i<20;i++){
terr>>number;
cc.push_back(number);
}
int M= cc.size;
cout<< M;
in this code, my vector size becomes 20; but there is not 20 columns. How can I know define that? I have to reach the vector elements by using like cc[M-3], cc[M-1]...