我的代码不断返回0作为文本文件中的小数位数

Question

I made a text file filled with decimals that are separated by a space and I want to count how many there are. the problem is when I came to check if I did it correctly the program says that the number of elements in the file is 0.

ifstream dataInput("Data Set.txt");
double readNumber;
vector<int> dataSet;
while (dataInput >> readNumber){
        dataSet.push_back(readNumber);
}
cout << "the Number of elements in this file is " << dataSet.size() << endl;

txt file:

3.2 1.9 2.7 2.4 2.8 2.9 3.8 3.0 2.5 3.3 1.8 2.5 3.7 2.8 2.0 3.2 2.3 2.1 2.5 1.9

My expected result is

The number of elements in this file is N.

but instead I get:

The number of elements in this file is 0.

EDIT: Thanks to the people on here I discovered that my file wasn't opening properly. I added the line

if (!dataInput.is_open()) {
    cerr << "The file can not be opened\n";
    exit(1);//exits the program
}

to check if the file opens properly.

Answer 1

As an advice you should get acquainted with the STL, but be aware that it takes some times to practice. At the end you will be able to write very concise code.

#include <iostream>
#include <fstream>
#include <vector>
#include <iterator>

int main() {
    std::ifstream dataInput("./data/TestFile.txt");
    if (!dataInput.good()) return EXIT_FAILURE;
    std::vector<double> dataSet;
    std::copy(std::istream_iterator<double>(dataInput), std::istream_iterator<double>(), std::back_inserter(dataSet));
    std::cout << "The number of elements in this file is: " << dataSet.size() << "\n";
    return EXIT_SUCCESS;
}

You shouldn't also write using namespace std in order to write less code. It is considered a bad practice.

Answer 2

Try to read your file correctly " ifstream dataInput("DataSet.txt"); " you should debug your code to know if you passe this condition

<< while (dataInput >> readNumber) >>