Question

使用以下代码，我正在读取.txt文件，但无法正确输出。如果我仅在项目名称（文本文件中的第二个项目）之后仅使用逗号定界符，它要么不能正确地中断第一个输入（使用所有逗号分隔符），要么不能正确地中断。

代码在这里：

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

int main()
{
    ifstream inventoryFile;
    string itemType[100], itemName[100], matCost[100], manHours[100];
//  float matCost[100], manHours[100];
    string temp;

    inventoryFile.open("items2.txt");

    cout << endl << endl;

    if(!inventoryFile)
    {
        cout << "\n\nCan't read from file.\n";
        exit(1);
    }
    int numItems=0;

    getline(inventoryFile, temp, ',');
    while(!inventoryFile.eof())
    {
        itemType[numItems] = temp;
        inventoryFile >> itemName[numItems];
        inventoryFile.ignore();
        inventoryFile >> matCost[numItems];
        inventoryFile.ignore();
        inventoryFile >> manHours[numItems];
        inventoryFile.ignore();
        numItems++;
        getline(inventoryFile, temp, ',');
    }

    for(int j=0; j<numItems; j++)
    {
        cout << "Item Type:\t" << itemType[j] << endl;
        cout << "ITem Name:\t" << itemName[j] << endl;
        cout << "Mats Cost:\t" << matCost[j] << endl;
        cout << "Man Hours:\t$" << manHours[j] << endl << endl; 
    }

    return 0;
}

items.txt文件是：

1, Xiphos, 7.46, 2
2, Dao, 3.45, 2.7
3, Jian, 2.31, 0.5
1, Rapier, 8.32, 2.3
2, Hook Sword, 2.11, 0.75
1, Panzerstecher, 2.23, 1.25
2, Kopis, 14.89, 2.3
3, Longsword, 5.43, 0.5
1, Tuck, 2.5, 15
1, Small Sword, 7.5, 2
3, Broadsword, 0.5, 0.25

items2.txt文件是：

1 Xiphos, 7.46 2
2 Dao, 3.45 2.7
3 Jian, 2.31 0.5
1 Rapier, 8.32 2.3
2 Hook Sword, 2.11 0.75
1 Panzerstecher, 2.23 1.25
2 Kopis, 14.89 2.3
3 Longsword, 5.43 0.5
1 Tuck, 2.5 15
1 Small Sword, 7.5 2
3 Broadsword, 0.5 0.25

Answer 1

这应该适用于items2.txt中的格式。

string itemType[100], itemName[100];
float matCost[100], manHours[100];
//...
//getline(inventoryFile, temp, ',');
// get itemType and the whitespace after it
while(inventoryFile >> itemType[numItems] >> std::ws)
{
    std::getline(inventoryFile, itemName[numItems], ',');
    inventoryFile >> matCost[numItems] >> manHours[numItems];
    // don't count this entry if the stream is in a failed state
    if(inventoryFile.fail()) break;
    inventoryFile.ignore();
    ++numItems;
}

Answer 2

对于items.txt，这应该有效：

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

using namespace std;

struct Row {
    int itemType;
    string itemName;
    float matCost;
    float manHours;
};

istream& operator>>(istream& in, Row& row){
    char comma;
    char firstCharOfName;
    in >> row.itemType >> comma >> firstCharOfName;
    in.putback(firstCharOfName);
    getline(in, row.itemName, ',');
    return in >> row.matCost >> comma >> row.manHours;
}

int main() {
    vector<Row> table;
    {
        ifstream inventoryFile("item.txt");
        string line;
        cout << "\n\n";

        if (!inventoryFile) {
            cerr << "\n\nCan't read from file.\n";
            return EXIT_FAILURE;
        }
        while (getline(inventoryFile, line)) {
            // make room for next row
            istringstream iss(line);
            table.resize(table.size() + 1U);
            Row &newRow = table.back();
            iss >> newRow;
            if (!iss) {
                // skip row on error
                table.resize(table.size() - 1U);
            }
        }
    }

    for (int j = 0; j < table.size(); j++) {
        cout << "Item Type:\t" << table[j].itemType << '\n'
             << "ITem Name:\t" << table[j].itemName << '\n'
             << "Mats Cost:\t$" << table[j].matCost << '\n'
             << "Man Hours:\t" << table[j].manHours << "\n\n";
    }

    return EXIT_SUCCESS;
}

PS：将$移至了Mats Cost。

C ++问题使用getline（）读取文件并正确格式化输出

2 个答案: