c - 我试图识别在 do-while 中输入的学生人数，并在循环外显示该数字

Question

我创建了一个接受用户输入的程序，并显示已输入的学生人数。

我使用 do-while 循环，因为在程序结束时会询问“你想继续吗？”如果用户输入 y，它将再次循环以获取输入。我尝试为其制作一个数组，但它无法很好地显示学生人数和平均成绩......

#include<stdio.h>


int main ()
{
    int student_id, test1,test2, final_mark;
    float total_up;
    char answer;


    do {

        printf("\nProgram to Calculate Student Grade\n");
        printf("Insert the student ID: ");
        scanf("%d",&student_id);
        printf("\nInsert marks for Test 1 (total of 25 ): ");
        scanf(" %d",&test1);
        if (test1 >25)
        {
            printf("The marks is greater than 25.Please re-insert it again.");
            printf("\nInsert marks for Test 1 (total of 25 ): ");
            scanf(" %d",&test1);
        }
           printf("\nInsert marks for Test 2 (total of 25 ): ");
           scanf(" %d",&test2);
           if (test2 >25)
        {
            printf("The marks is greater than 25.Please re-insert it again.");
            printf("\nInsert marks for Test 2 (total of 25 ): ");
            scanf(" %d",&test2);
        }
            printf("\nInsert marks for Final Exam: (total of 50): ");
            scanf(" %d",&final_mark);
            if ( final_mark > 50 )
            {
                printf("\nThe Final Exam is greater than 50. Please re-insert it again.");
                printf("\nInsert marks for Final Exam: (total of 50) ");
                scanf("%d",&final_mark);
            }

        total_up = test1 + test2 + final_mark;
        printf("Total Marks: %.2f",total_up);
        if (total_up >=80)
        {
            printf("\nGrade is A\n");
        }
        else if (total_up >=60)
        {
            printf("\nGrade is B\n");
        }
        else if (total_up >=50)
        {
            printf("\nGrade is C\n");
        }
        else if (total_up >=40)
        {
            printf("\nGrade is D\n");
        }
        else if (total_up <40)
        {
            printf("\nGrade is F\n");
        }

        printf("Do you want to continue? ");
        scanf(" %c",&answer);
    }while (answer == 'y' || answer == 'Y');

        printf("\nTotal number of students entered is %d ", student_id);
        total_up = total_up / 2;
        printf("\nTotal number of students entered is %.2f ",total_up);
    return 0;
}

假设输入为:

Program to Calculate Student Grade 
Insert the student ID : 123 
Insert marks for Test 1 ( total of 25 ): 15
Insert marks for Test 2 ( total of 25 ): 20

Insert marks for Final Exam ( total of 50 ): 42

Total Marks : 77.00 
Grade is B 

Do you want to continue ? y 

Program to Calculate Student Grade 
Insert the student ID : 456
Insert marks for Test 1 ( total of 25 ): 21
Insert marks for Test 2 ( total of 25 ): 23

Insert marks for Final Exam ( total of 50 ): 47

Total Marks : 91.00 
Grade is A 

Do you want to continue ? n 

所以，在 do-while 终止之后..我期望的是

Total number of students entered is 2
Total number of students entered is 84.00 

Average grade is A   

我为学生和测试尝试了一个数组，但它可能不起作用..有什么想法吗？

Answer 1

为了计算学生数量和计算小计，需要两个额外的变量并在循环外将它们初始化为 0。然后，在循环内部，随着循环的每次迭代增加student_count，并将当前学生的总分与计算小计的变量相加。最后，很容易计算平均值。只需将小计除以学生人数即可。

此外，为了计算成绩，您可以将其保留在另一个函数中，因为您必须执行两次，一次在循环内，另一次在循环外。

#include <stdio.h>
void showGrade(float marks)
{
    if (marks >= 80) {
        printf("Grade is A\n");
    }
    else if (marks >= 60) {
        printf("Grade is B\n");
    }
    else if (marks >= 50) {
        printf("Grade is C\n");
    }
    else if (marks >= 40) {
        printf("Grade is D\n");
    }
    else if (marks < 40) {
        printf("Grade is F\n");
    }
}
int main()
{
    int student_id, test1, test2, final_mark, student_count = 0;
    float total_up, grand_total = 0, average;
    char answer;
    do {
        student_count++;
        printf("\nProgram to Calculate Student Grade\n");
        printf("Insert the student ID: ");
        scanf("%d", &student_id);
        printf("\nInsert marks for Test 1 (total of 25 ): ");
        scanf(" %d", &test1);
        if (test1 > 25) {
            printf("The marks is greater than 25. Please insert it again.");
            printf("\nInsert marks for Test 1 (total of 25): ");
            scanf(" %d", &test1);
        }
        printf("Insert marks for Test 2 (total of 25 ): ");
        scanf(" %d",&test2);
        if (test2 > 25) {
            printf("The marks is greater than 25. Please insert it again.");
            printf("\nInsert marks for Test 2 (total of 25): ");
            scanf(" %d", &test2);
        }
        printf("Insert marks for Final Exam: (total of 50): ");
        scanf(" %d", &final_mark);
        if (final_mark > 50) {
            printf("\nThe Final Exam is greater than 50. Please insert it again.");
            printf("\nInsert marks for Final Exam: (total of 50): ");
            scanf("%d", &final_mark);
        }
        total_up = test1 + test2 + final_mark;
        grand_total += total_up;
        printf("\nTotal Marks: %.2f\n", total_up);
        showGrade(total_up);
        printf("\nDo you want to continue? ");
        scanf(" %c", &answer);
    } while (answer == 'y' || answer == 'Y');
    printf("\nTotal number of students entered is %d ", student_count);
    average = grand_total / student_count;
    printf("\nAverage total number of students entered is %.2f\n", average);
    printf("\nAverage ");
    showGrade(average);
    return 0;
}