如何从文件中读取两个字符串和数字数组并将它们存储在对象向量中

Question

I have a simple structure in my code to read the values from a txt file. this struct is

struct read_data_into_file{
std::string Fname,Lname;
double score[5];
double sum;
};

then I have a function to open and read from the file.

void ReadFromFile(){
std::ifstream f;
read_data_into_file Newobj;
std::vector<read_data_into_file> obj;
f.open("/Users/vibhorsagar/Desktop/cslabs/cs-116lab1/cs-116lab1/input.txt");
if(!f.is_open())
{
    std::cout<<"error opening file";

}
else{
    while(!f.eof())
    {
        f>>Newobj.Fname>>Newobj.Lname;
        for(count=0;count<5;count++)
        {
        f>>Newobj.score[count];
            Newobj.sum+=Newobj.score[count];
        }
        obj.push_back(Newobj);
    }
        for(int i=0;i<obj.size();i++){
        std::cout<<obj[i]<<" "<<std::endl;

    }
}
f.close();

I am kinda confused on how to read the data in the vector. The text file contains a bunch of names and numbers.

Andria Senger 80 65 81 76

Nathalie Witherspoon 96 99 93

Maribel Danner 94 53 96 91 60

Kara Hogan 52 75 93 97 95

Elliot Kremer 74 50 96 68

Keena Scheurer 100 90 57 97 90

Sindy Morfin 74 67

Janeth Saito 81 60 60

These are the contents of the txt file. I was thinking I could store individual name as a first name and a last name and the numbers after that into an array. and then find their individual average. but when I try to print the vector in the function I get an error

Invalid operands to binary expression ('std::__1::ostream' (aka 'basic_ostream') and 'std::__1::__vector_base >::value_type' (aka 'read_data_into_file'))

Also the numbers in each line are not 5, but I am using that for the array size because that was the highest number in a line. I don't know how to dynamically set the array size for each line. I am using Xcode on Mac to write and compile.

if there is any other way to do this, I can use the help or if you can suggest a better way to do this. Thank You!

Answer 1

There are some things to consider with your problem. First, you must account for the different amount of scores in each file entry. Also, you have to deal with empty lines in the file.

The code below will make it work for your problem.

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

void ReadFromFile(){
    std::vector<read_data_into_file> obj;

    std::ifstream inFile;
    inFile.open("input.txt");

    while(!inFile.eof())
    {
        std::string curLine;
        std::getline(inFile, curLine);

        if (!curLine.size())
            continue;

        std::stringstream curStr(curLine);

        read_data_into_file newObj;
        curStr >> newObj.Fname;
        curStr >> newObj.Lname;

        int i = 0;
        while (curStr.good()) {
            curStr >> newObj.score[i++];
        }

        newObj.sum = 0;
        while (i--) {
            newObj.sum += newObj.score[i];
        }

        obj.push_back(newObj);
    }

    inFile.close();

    for (auto& p : obj) {
        std::cout << p.Fname << " " << p.Lname << " " << p.sum << std::endl;
    }
}

However, a proper solution would be to use an std::vector<double> score; instead of double score[5]; in your read_data_into_file structure. Then your code will be:

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

struct read_data_into_file{
std::string Fname,Lname;
std::vector<double> score;
double sum;
};

void ReadFromFile(){
    std::vector<read_data_into_file> obj;

    std::ifstream inFile;
    inFile.open("input.txt");

    while(!inFile.eof())
    {
        std::string curLine;
        std::getline(inFile, curLine);

        if (!curLine.size())
            continue;

        std::stringstream curStr(curLine);

        read_data_into_file newObj;
        curStr >> newObj.Fname;
        curStr >> newObj.Lname;

        while (curStr.good()) {
            double curScore;
            curStr >> curScore;
            newObj.score.push_back(curScore);
        }

        newObj.sum = 0;
        for (auto& s : newObj.score)
            newObj.sum += s;

        obj.push_back(newObj);
    }

    inFile.close();

    for (auto& p : obj) {
        std::cout << p.Fname << " " << p.Lname << " " << p.sum << std::endl;
    }
}