c++ - 重新定义格式参数错误

Question

这是我要解决的问题的图像:http://i.imgur.com/WLHntVC.png

我已经完成了相当多的工作，但真的卡住了。

我目前的代码如下

头文件:voter.h

#include <string>
#include <iostream>
#include <vector>
class Voter {
    int id;
    std::string votes;

public:
    Voter(int id, std::string votes) {
        this->id = id;
        this->votes = votes;
    }

    char getVote(int i) {
        return votes[i];
    }

    std::string getVotes() { 
        return votes; 
    }

    int getID() {
        return id;
    }
};

Source1.cpp

#include "Voter.h"
#include <fstream>
#include <algorithm>
#include <iomanip>

const int TALLY_MAX = 9;

void readFile(std::string fileName, Voter** v, int& size) {
    std::ifstream is(fileName);
    Voter** v = nullptr;

    int id;
    size = 0;
    std::string str;

    while (!is.eof()){
        std::getline(is,str);
        size++;
    }

    v = new Voter*[size];

    int i = 0;

    while (!is.eof()){
        is >> id >> str;
        v[i] = new Voter(id, str);
        i++;
    }

for(int i = 0; i < size; i++)
    delete v[i];
delete [] v;
}


void tallyVotes(std::vector<Voter> v, int tally[]) {
    for (int i = 0; i < v.size(); i++) {
        for (int j = 0; j < TALLY_MAX/2; j++) {
            int vote = v[i].getVote(j) - 'A';
            tally[vote]++;
        }
    }
}

// sort using a custom function object
struct {
    bool operator()(Voter a, Voter b)
    {
        return a.getID() < b.getID();
    }
} customLess;

int main(){
    std::vector<Voter> v = readFile("votes.txt");
    int tally[TALLY_MAX];

    for (int i = 0; i < TALLY_MAX; i++)
        tally[i] = 0;

    tallyVotes(v, tally);

    std::sort(v.begin(), v.end(), customLess);

    for (int i = 0; i < v.size(); i++) {
        std::cout << std::setfill('0') << std::setw(4) << v[i].getID() << " " << v[i].getVotes() << "\n";
    }

    std::cout << "\n\nVote Totals\n";

    for (int i = 0; i < TALLY_MAX; i++)
        std::cout << (char)(i + 'A') << " " << tally[i] << "\n";

    //return 0;   
    std::cin.get();
    std::cin.ignore();
}

如有任何帮助，我们将不胜感激。

Answer 1

让我们从头开始。此函数不会按照您在代码中定义它的方式被调用。

int main(){
    std::vector<Voter> v = readFile("votes.txt");
    ...
}

您的函数需要三个参数并删除结果。你想在这里返回什么 void (结果是指针参数)或 std::vector< Voter > (希望是右值移动)？

void readFile(std::string fileName, Voter** v, int& size) {
    std::ifstream is(fileName);
    Voter** v = nullptr;

    int id;
    size = 0;
    std::string str;

    while (!is.eof()){
        std::getline(is,str);
        size++;
    }

    v = new Voter*[size];

    int i = 0;

    while (!is.eof()){
        is >> id >> str;
        v[i] = new Voter(id, str);
        i++;
    }

for(int i = 0; i < size; i++)
    delete v[i];
delete [] v;
}

也许你想要的是:

std::vector< Voter > readFile(const std::string & fileName) {
    std::ifstream is(fileName);
    std::vector< Voter > v;

    int id;
    std::string str;

    while (is.good()) {
        is >> id >> str;
        v.push_back( Voter( id, str ) ); 
    }
    return v;
}