如何从C ++中的函数返回结构？ [英] How to return a struct from a function in C++?

问题描述

我试过几个不同的论坛，似乎无法得到直接的答案，我该如何让此函数返回结构体？如果我尝试'返回newStudent;'我收到错误'没有合适的用户定义从studentType到studentType的转换存在。'

  //输入函数
 studentType newStudent（）
 {
 struct studentType 
 {
 string studentID; 
字符串firstName; 
字符串lastName; 
 string subjectName; 
字符串courseGrade; 
 
 int arrayMarks [4]; 
 
 double avgMarks; 
 
} newStudent; 
 
 cout<< \\\
请输入学生信息：\\\
; 
 
 cout<< \\\
First Name：; 
 cin>> newStudent.firstName; 
 
 cout<< \\\
Last Name：; 
 cin>> newStudent.lastName; 
 
 cout<< \学生ID：; 
 cin>> newStudent.studentID; 
 
 cout<< \主题名称：; 
 cin>> newStudent.subjectName; 
 
 for（int i = 0; i  {cout<< \\\
Test<< i + 1<< mark：; 
 cin>> newStudent.arrayMarks [I]; 
} 
 
 newStudent.avgMarks = calculate_avg（newStudent.arrayMarks，NO_OF_TEST）; 
 newStudent.courseGrade = calculate_grade（newStudent.avgMarks）; 
 
 
 $ / code $ / pre 
 
解决方案
您的代码编辑版本基于 ISO C ++ ，可与G ++一起使用： 
 
 
  #include< string.h> 
 #include< iostream> 
使用namespace std; 
 
 #define NO_OF_TEST 1 
 
 struct studentType {
 string studentID; 
字符串firstName; 
字符串lastName; 
 string subjectName; 
字符串courseGrade; 
 int arrayMarks [4]; 
 double avgMarks; 
}; 
 
 studentType input（）{
 studentType newStudent; 
 cout<< \\\
请输入学生信息：\\\
; 
 
 cout<< \\\
First Name：; 
 cin>> newStudent.firstName; 
 
 cout<< \\\
Last Name：; 
 cin>> newStudent.lastName; 
 
 cout<< \学生ID：; 
 cin>> newStudent.studentID; 
 
 cout<< \主题名称：; 
 cin>> newStudent.subjectName; 
 
 for（int i = 0; i  cout<< \\\
Test<< i + 1<< mark：; 
 cin>> newStudent.arrayMarks [I]; 
} 
 
返回newStudent; 
} 
 
 int main（）{
 studentType s; 
 s = input（）; 
 
 cout<<\\\
 ========<< endl<< 收集
<< s.firstName<< ENDL; 
 
返回0; 
} 
  
 
I've tried on a few different forums and can't seem to get a straight answer, how can I make this function return the struct? If I try 'return newStudent;' I get the error 'No suitable user-defined conversion from studentType to studentType exists.'
// Input function
studentType newStudent()
{   
    struct studentType
    {
        string studentID;
        string firstName;
        string lastName;
        string subjectName;
        string courseGrade;

        int arrayMarks[4];

        double avgMarks;

    } newStudent;

    cout << "\nPlease enter student information:\n";

    cout << "\nFirst Name: ";
    cin >> newStudent.firstName;

    cout << "\nLast Name: ";
    cin >> newStudent.lastName;

    cout << "\nStudent ID: ";
    cin >> newStudent.studentID;

    cout << "\nSubject Name: ";
    cin >> newStudent.subjectName;

    for (int i = 0; i < NO_OF_TEST; i++)
    {   cout << "\nTest " << i+1 << " mark: ";
        cin >> newStudent.arrayMarks[i];
    }

    newStudent.avgMarks = calculate_avg(newStudent.arrayMarks,NO_OF_TEST );
    newStudent.courseGrade = calculate_grade (newStudent.avgMarks);

}

解决方案
Here is an edited version of your code which is based on ISO C++ and which works well with G++:
#include <string.h>
#include <iostream>
using namespace std;

#define NO_OF_TEST 1

struct studentType {
    string studentID;
    string firstName;
    string lastName;
    string subjectName;
    string courseGrade;
    int arrayMarks[4];
    double avgMarks;
};

studentType input() {
    studentType newStudent;
    cout << "\nPlease enter student information:\n";

    cout << "\nFirst Name: ";
    cin >> newStudent.firstName;

    cout << "\nLast Name: ";
    cin >> newStudent.lastName;

    cout << "\nStudent ID: ";
    cin >> newStudent.studentID;

    cout << "\nSubject Name: ";
    cin >> newStudent.subjectName;

    for (int i = 0; i < NO_OF_TEST; i++) {
        cout << "\nTest " << i+1 << " mark: ";
        cin >> newStudent.arrayMarks[i];
    }

    return newStudent;
}

int main() {
    studentType s;
    s = input();

    cout <<"\n========"<< endl << "Collected the details of "
        << s.firstName << endl;

    return 0;
}


                        
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