Question

我正在阅读一个文件和格式化数组，所以我可以用其他东西来处理它们但我一开始就陷入困境。它说我不能从char *更改为char但我的令牌不是char *。

#include <iostream>
#include <fstream>
#include <sstream>
#include <cstring>
#include <string>
#include <stdio.h>

using namespace std;

void get_input(string teams[][2]) {
    string infile;
    double value;   
    char buffer[100];
    char token;
    stringstream ss;
    cout << "Enter the input file: ";
    cin >> infile;
    ifstream file;
    file.open (infile.c_str());
    if (file.is_open()) {
        int teamcounter = 0;
        while (file.getline (buffer, 100)) {
            int counter = 0;
            token = strtok (buffer, ",");
            while (token) {
                if (counter == 0) {
                    teams[teamcounter][counter] = token;
                }
                else if ((counter == 1) || (counter == 2)) {
                    ss << token;
                    ss >> value;
                    teams[teamcounter][counter] = value;
                }
                token = strtok (NULL, ",");
                counter++;
            }
            teamcounter++;
        }
        file.close();
    }
    else {
        cout << "Unable to open file"; 
    }

    for (int i = 0; i< 7; i++){
        for (int j = 0; j<2;j++){
            cout << teams[i][j] << " ";
        }
        cout << endl;
    }
}

将我的数组变成字符串使我无法将float或double值赋予它们吗？

int main() {
    cout << "Welcome to the football bracket game!" << endl;
    string teams[7][2];
    get_input(teams);
}

我的输入文字格式如下：

Trojans, 0.80, 0.60
Bruins, 0.20, 0.30
Bears, 0.60, 0.50
Trees, 0.50, 0.40
Ducks, 0.40, 0.80
Beavers, 0.50. 0.10
Huskies, 0.80, 0.40
Cougars, 0.10, 0.90

Answer 1

char token;
token = strtok (buffer, ",");

token的类型为char，strtok返回char*。它们的类型不同，编译器（逻辑上）抱怨它。 strtok返回指向已处理输入char*的下一个标记的指针，所以确实将它分配给单个字符是没有意义的。

编译器确实无法找到从返回char*转换为char的方法，错误中没有什么奇怪的。

Answer 2

strtok()会返回char*，但您的token变量会被声明为char。它需要声明为char*。

更新：由于您使用的是C ++，我强烈建议您使用C ++，不要将C和C ++混合在一起。忽略strtok()甚至存在，例如：

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

struct Team
{
    std::string Name;
    double Value1;
    double Value2;
};

void get_input(std::vector<Team> &teams)
{
    std::string infile;
    std::ifstream file;

    std::cout << "Enter the input file: ";
    std::cin >> infile;

    file.open (infile.c_str());
    if (!file.is_open())
    {
        std::cout << "Unable to open file"; 
        return;
    }

    std::string line;
    while (std::getline(file, line))
    {
        Team team;
        std::istringstream ss(line);
        std::string token;
        int counter = 0;

        while (std::getline(ss, token, ","))
        {
            switch (counter)
            {
                case 0:
                    team.Name = token;
                    break;
                case 1:
                    std::stringstream(token) >> team.Value1;
                    break;
                case 2:
                    std::stringstream(token) >> team.Value2;
                    break;
            }
            ++counter;
        }
        teams.push_back(team);
    }
}

int main()
{
    std::cout << "Welcome to the football bracket game!" << std::endl;
    std::vector<Team> teams;
    get_input(teams);

    for (std::vector<Team>::iterator iter = teams.begin(); iter != teams.end(); ++iter)
    {
        std::cout << iter->Name << ": " << iter->Value1 << " " iter->Value2 << std::endl;
    }
}

Answer 3

您将变量标记定义为类型char

char token;

while函数strtok返回类型char *的obhect。这些语句

token = strtok (buffer, ",");

和

token = strtok (NULL, ",");

无效。我想你的意思是

char *token;

您还将阵列团队定义为std::string

类型的元素数组

string teams[7][2];

但是在函数get_input中，您尝试将类型为double的值赋给std :: string

类型的对象

double value;
//...
teams[teamcounter][counter] = value;

如果函数有第二个参数指定数组第一维的大小，那么它会更正确

void get_input(string teams[][2], int n );

并将被称为

get_input(teams, 7);

您应该检查您输入的文件的行数。

错误：第26,36行从'char *'无效转换为'char'

3 个答案: