c - 如何在 C 中打印结构体的内容？

Question

我自己解决了问题，使用的方法与下面建议的方法不同! :)

感谢您查看我的问题! :)

我一直在学习结构体并在 C 语言的实践实验室中工作，但我的代码似乎无法通过我对其所做的任何更改正确编译。 目前我没有收到任何输出，程序崩溃了。我仍然对如何在将“*”和“&”符号传递给函数时正确使用它们感到非常困惑。我的这种做法的目标是:

• 以与数据文件相同的格式打印数组内容
• 打印出 GPA 最高的学生的全名
• 计算并打印平均 GPA
• 打印出所有 GPA 高于平均水平的学生的姓名
• 打印 GPA 低于平均水平的最小学生的姓名
• 将数组中的结构按从低到高的顺序排序平均绩点
• 再次打印数组(现在的顺序与上次的顺序不同)时间)

如何正确调用并打印学生结构中的这些项目？我如何访问 gpa 值并将其传递给计算平均值的函数？

#include <stdio.h>
#include <stdlib.h>

// define constants
#define ARR 100
#define FIRST 7
#define MIDINIT 1
#define LAST 9
#define STREET 16
#define CITY 11
#define STATE 2
#define ZIP 5
#define AGE 3
#define GPA 4
#define START 0
#define FIRSTID 8
#define INITID 10
#define STREETID 20
#define CITYID 37
#define STATEID 49
#define ZIPID 52
#define AGEID 57
#define GPAID 64

// defined structs

typedef struct {
    char street[STREET + 1];
    char city[CITY + 1];
    char state[STATE + 1];
    char zip[ZIP + 1];  
} Address;

typedef struct {
    char firstname[FIRST + 1];
    char initial[MIDINIT + 1];
    char lastname[LAST + 1];
    Address ofstudent;
    int age;
    double gpa;
} Student;

// function prototype
void strsub(char buf[], char s[], int start, int size); 
void processStudent(int *id, Student students[]);
void sortStudentGpa(Student *students, int id); 
void maxGpa(Student *students, int id);

/* lab6student.c: creates an array of student structures and outputs reports */
int main(void)
{
    Student students[ARR]; // creates an array of student structures
    int id = 0; // counter for student

    processStudent(&id, students);
    maxGpa(students, id);
}
void strsub(char buf[], char s[], int start, int size) {
    int i;

    for (i = 0; i < size && buf[start + i] != '\0'; i++) { 
        // loops as long as iterator is less than size 
        // and while string has not run out of characters
        s[i] = buf[i + start];
    }
    s[i] = '\0';
}
/* void sort(Student *students, int id) {
    int j, i;

    for(i = 1; i < n; i++) {
        for(j = 0; j < id - i; j++) {
            if(students[j].gpa > students[j + 1].gpa) {
                Student temp = students[j];
                students[j] = students[j + 1];
                students[j + 1] = temp;
            }
        }
    }
} */
void processStudent(int *id, Student students[]) {
    FILE *data;
    char line[ARR];
    *id = 0; // counter for student

    data = fopen("Students.dat", "r");
    if (data == NULL) {
        printf("Students.dat file not found!\n");
        exit(1);
    }

    // process file
    while (!feof(data)) {
        // organize student info into separate arrays
        fgets(line, ARR, data);
        strsub(line, students[*id].firstname, START, FIRST); 
        strsub(line, students[*id].initial, FIRSTID, MIDINIT);
        strsub(line, students[*id].lastname, INITID, LAST);
        strsub(line, students[*id].ofstudent.street, STREETID, STREET);
        strsub(line, students[*id].ofstudent.city, CITYID, CITY);
        strsub(line, students[*id].ofstudent.state, STATEID, STATE);
        strsub(line, students[*id].ofstudent.zip, ZIPID, ZIP);
        students[*id].age = atoi(&line[AGEID]);
        students[*id].gpa = atoi(&line[GPAID]);
        (*id)++;
    }   

    fclose(data);
}
//sorts struct student array containing num (gpa) elements into
//ascending order
void sortStudentGpa(Student *students, int id) {
    int i, j; // indexes into unsorted and sorted partitions
    Student temp; // temporarily holds an element from the array

    for (i = 1; i < id; ++i) {
        temp = students[i];
        j = i - 1;
        while (j >= 0 && temp.gpa < students[j].gpa) {
            students[j + 1] = students[j];
            j = j - 1;
        }
        students[j + 1] = temp;
    }
} 
void maxGpa(Student *students, int id) {
    int iwithmax, i;
    float max = 0;

    for ( i = 0 ; i < id ; i++) {
        if (students -> gpa > max) {
            max = students -> gpa;
            iwithmax = i;
        }
    }

    printf("\n\nHighest GPA is done by Student %d with GPA = %f", iwithmax, max);
}

Answer 1

在 maxGpa 函数中只需将定义更改为

        void maxGpa(Student *students, int id);

然后在 maxGpa 函数中进行以下更改

   void maxGpa(Student *students, int id) {
    int iwithmax, i;
    float max = 0;

    for ( i = 0 ; i < id ; i++) {
            if (students -> gpa > max) {
                    max = students -> gpa;
                    iwithmax = i;
            }
    }

试试这个......