Question

我是c ++的新手，试图了解名称空间和类。我这里有2个课程两个都在不同的文件中。

第一个是

 #include<iostream>

using namespace std;

namespace project{
 class Student{
    string name,address,enrolmentDate ,usn;
    int hours;
    public:
    Student(char* nusn, char* nname, char* naddress, char* ndate,int nhours){
        usn = nusn;
        name = nname;
        address = naddress;
        enrolmentDate = ndate;
        hours = nhours;
    }
    Student(){
        getData();
    }
    void getData(){
        std::cout << "Enter Usn,Name,Address,EnrolmentDate,Hours\n";
        std::cin >> usn >> name >> address >> enrolmentDate >> hours;
    }
    string getName(){
        return name;
    }
    string getAddress(){
        return address;
    }
    string getenrolmentDate(){
        return enrolmentDate;
    }
    int getHours(){
        return hours;
    }
    string getUsn(){
        return usn;
    }
 };
}

第二课是

    #include<iostream>

using namespace std;

namespace project{
    class CourseRegistration{
    string usn, courseId ;
    int hours, grade;
    public:
    CourseRegistration(project::Student obj, string courseId, int nhours, int ngrade){
       usn = obj.getUsn();
       this->courseId = courseId;
       hours = nhours;
       grade = ngrade;
    }
    };
}

First class Compiles fine.But第二个类给出错误错误就在学生对象附近。

Course.cpp:10:38: error: expected ‘)’ before ‘obj’
  CourseRegistration(project::Student obj, string courseId, int nhours, int ngrade){

我如何纠正它？

Answer 1

我没有看到任何证据表明您在第二个文件中包含了Student的定义。您的类应在头（.h）文件中声明，并在源（.cpp）文件中实现。您的编译器可能会抱怨，因为它不知道Student是一个类。

<强> Student.h

#include<iostream>

using namespace std;

namespace project {
    class Student {
    private:
        string name,address,enrolmentDate, usn;
        int hours;
    public:
        Student( char*, char*, char*, char*, int );
        Student();
        void getData();
        string getName();
        string getAddress();
        string getenrolmentDate();
        int getHours();
        string getUsn();
    }
}

<强> Student.cpp

#include "Student.h"

namespace project {

Student::Student( char* nusn, char* nname, char* naddress, char* ndate,int nhours ) {
    usn = nusn;
    name = nname;
    address = naddress;
    enrolmentDate = ndate;
    hours = nhours;
}

Student() {
    getData();
}

void getData() {
    std::cout << "Enter Usn,Name,Address,EnrolmentDate,Hours\n";
    std::cin >> usn >> name >> address >> enrolmentDate >> hours;
}

string getName() {
    return name;
}

string getAddress() {
    return address;
}

string getenrolmentDate() {
    return enrolmentDate;
}

int getHours() {
    return hours;
}

string getUsn() {
    return usn;
}

}

<强> CourseRegistration.h

#include "Student.h"
#include<iostream>

using namespace std;

namespace project{
    class CourseRegistration {
    private:
        string usn, courseId ;
        int hours, grade;
    public:
        CourseRegistration( Student, string, int, int );
    }
}

<强> CourseRegistration.cpp

#include<CourseRegistration.h>


namespace project {
    CourseRegistration::CourseRegistration( Student obj, string courseId, int nhours, int ngrade ) {
        usn = obj.getUsn();
        this->courseId = courseId;
        hours = nhours;
        grade = ngrade;
    }
}

在c ++中将对象作为参数传递

1 个答案: