功能调用，该函数从文本文件-C 检查输入正确性

Function Call That Checks For Input Correctness From Text File - C++

本文关键字：文件 检查 输入 正确性 文本 调用 函数 功能      更新时间：2023-10-16

如果" insert_employee"下方的数据足以将其输入我的" Insertemployee"函数，该如何检查文本文件？（示例：正确的数字，参数类型或检查参数边界）另外，如果输入是无效的格式，我不想执行操作，而只是跳过下一个操作。

我的文本文件：

INSERT_EMPLOYEE
12345
John
Smith
60000
35
INSERT_EMPLOYEE
Chris
Evans
70000
INSERT_EMPLOYEE
34567
Michael
Carter
50500
25
PRINT_ROSTER

我的main.cpp：

#include <iostream>
#include <fstream>
using namespace std;
int main() {
    int id, salary, hours;
    employeeList list = employeeList();
    string line, firstName, lastName;
    ifstream employeeFile;
    employeeFile.open("employeeFile.txt");
    while(getline(employeeFile, line)) {
        if (line == "INSERT_EMPLOYEE") {
            employeeFile >> id >> firstName >> lastName >> salary >> hours;
            list.insertEmployee(id, firstName, lastName, salary, hours);
        }
        if (line == "PRINT_ROSTER") {
            list.printRoster();
        }
    employeeFile.close();
    return 0;
}

每当您想根据语法解析/验证输入时，请考虑使用解析器。

写解析器很乏味。因此，请考虑使用解析器。由于您正在编写C ，因此请考虑您即时编译的一种，例如使用Boost Spirit：

活在coliru 

#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/qi_match.hpp>
#include <iostream>
#include <fstream>
namespace qi = boost::spirit::qi;
struct Employee {
    unsigned id;
    std::string firstname, surname;
    double salary;
    unsigned hours;
};
static inline std::ostream& operator<<(std::ostream& os, Employee const& emp) {
    return os << "Employee (" 
        << emp.id << " " 
        << emp.firstname << " " 
        << emp.surname << " " 
        << emp.salary << " " 
        << emp.hours << ")";
}
struct employeeList {
    std::vector<Employee> employees;
    void printRoster() const {
        std::cout << "nRoster:n";
        for (auto& emp : employees)
            std::cout << emp << "n";
    }
};
namespace parser {
    using namespace boost::spirit::qi;
    auto const INSERT = copy(uint_ >> eol >> +graph >> eol >> +graph >> eol >> double_ >> eol >> uint_);
}
int main() {
    employeeList list = employeeList();
    std::string line, firstName, lastName;
    std::ifstream input("employeeFile.txt");
    input.unsetf(std::ios::skipws);
    std::string command;
    while (getline(input, command)) {
        if (command == "INSERT_EMPLOYEE") {
            Employee emp;
            if (input >> qi::phrase_match(parser::INSERT, qi::blank, emp.id, emp.firstname, emp.surname, emp.salary, emp.hours)) {
                std::cout << "Added " << emp << "n";
                list.employees.push_back(emp);
            }
            else {
                std::cout << "Ignoring invalid INSERT_EMPLOYEE commandn";
                input.clear();
                input.ignore(1024, 'n');
            }
        }
        if (command == "PRINT_ROSTER") {
            list.printRoster();
        }
        // skip any non-valid lines until empty line
        while (getline(input, command)) {
            if (command.empty())
                break;
            //else std::cout << "Skipping over input '" << command << "'n";
        }
    }
}

对于给定样品输入，它打印：

Added Employee (12345 John Smith 60000 35)
Ignoring invalid INSERT_EMPLOYEE command
Added Employee (34567 Michael Carter 50500 25)
Roster:
Employee (12345 John Smith 60000 35)
Employee (34567 Michael Carter 50500 25)
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