C++ |一个数组，switch 语句？需要一些指导

Question

我的目标是选出 (3) 名学生，给他们每个人打 (3) 分，然后是每个学生的平均分以及字母等级。这部分效果很好。我需要的最后一部分是取这 (3) 个平均成绩，将它们相加，然后取另一个平均值，这将是类(class)平均成绩。

我应该如何获得类(class)平均分？大批？开关语句？我问的原因是因为我真的不知道。我对如何实现这一点一无所知。

#include <iostream>
#include <ostream>
#include "stdafx.h"
using namespace std;

// start the program
int main() {
    // LOCAL VARIABLES
    // int student1, student2, student3;     //the (3) students -- NOT EVEN SURE
    // I NEED THIS
    int all_students; // number of students
    double grade1, grade2, grade3; // the (3) grade variable declarations
    double grade_total; // holds the sum of all grades
    double grade_avg; // holds the average of the sum of grades

    cout << "Enter the number of students in the class: "; // number of students
                                                           // request
    cin >> all_students;

    all_students = 1; // initialize counter for the loop

    // need to create a loop for all three students and input for 3
    // grades/student
    while (all_students <= 3) // start the loop for the students
    {
        cout << "\n\nPlease enter (3) numeric grades for student "
             << all_students << ":"; // enters the 3 grades for student
        cin >> grade1 >> grade2 >>
            grade3; // the grades are stored in these 3 variables

        grade_total = grade1 + grade2 +
                      grade3; // sum is the 3 sets of graders added together
        grade_avg = grade_total / 3; // avg. is the sum divided by 3

        // displays the output for the student grades, grade average, and letter
        // grade
        cout << "Student " << all_students << " grades are \n" << grade1 << "\n"
             << grade2 << "\n" << grade3 << "\n"
             << "with an average of: " << grade_avg
             << ", which is letter grade: "; // need this line to also read the
                                             // letter grade for the average
                                             // grade

        if (grade_avg >= 90) // 90+ gets an A
            cout << "A";
        else if (grade_avg >= 80) // 80-89 gets a B
            cout << "B";
        else if (grade_avg >= 70) // 70-79 gets a C
            cout << "C";
        else if (grade_avg >= 60) // 60-69 gets a D
            cout << "D";
        else // anything less than a 60% is an F
            cout << "F";

        // increases counter!  Incrementer.
        all_students++; // Yes, I want to increment the count after the loop.

        //****************************************************************//
        //      I need to figure out how to create an array to hold       //
        //      each student average in order to calculate the overall    //
        //      class average.  Or use a switch statement?  Advice?       //
        //****************************************************************//
        //****************************************************************//
        //****************************************************************//
    }
}

Answer 1

您需要在 while 外部创建一个包含最大学生数的数组，然后在 while 循环内部(在它的末尾)将每个计算的平均值分配给该数组中的一个条目。

然后在while循环外，写一个for循环，计算数组中元素的平均值，也就是每个学生的平均值