如何将文件逐行读入向量然后打印向量

Question

I'm trying to read in a file, add each line into a vector, and then print the vector. But right now, it will only print the first line. Because of this, I'm assuming that the first line is the only line being added to the vector, but I can't figure out why.

Here is my code:

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using namespace std;

int main()
{
    std::vector<std::string> vecOfStrs;

    std::ifstream fileIn("example.txt");
    std::string str;
    std::string newLine;
    newLine = str + "\n";

    while (std::getline(fileIn, str)) {
        std::string newLine;
        newLine = str + "\n";
        if (newLine.size() > 0) {
            vecOfStrs.push_back(newLine);
        }
        fileIn.close();
        for (int i = 0; i < vecOfStrs.size(); i++) {
            std::cout << vecOfStrs.at(i) << ' ';
        }
    }
}

Here is the text file, and right now it should print out exactly as it appears here:

Barry Sanders
1516 1319 1108 1875 -999
Emmitt Smith
1892 1333 1739 1922 1913 1733 -999
Walter Payton
1999 1827 1725 1677 -999

Answer 1

There is logic inside of your reading loop that really belongs after the loop has finished instead:

• You are close() 'ing the file stream after the 1st line is read, thus breaking the loop after the 1st iteration.

• You are printing the entire vector after adding each line to it.

Also, you don't need the newLine variables at all.

Try this instead:

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
using namespace std;

int main() {
    std::vector<std::string> vecOfStrs;
    std::ifstream fileIn("example.txt");
    std::string str;

    while (std::getline(fileIn, str)) {
        if (str.size() > 0) {
            vecOfStrs.push_back(str);
        }
    }

    fileIn.close();

    for (size_t i = 0; i < vecOfStrs.size(); i++) {
        std::cout << vecOfStrs[i] << ' ';
    }

    return 0;
}