我正在编写这本成绩簿程序而且我无法确定我的错误在哪里。我没有正确显示结果。以下是我应该运行的示例以及结果应该是什么样的:
ID, NAME, GRADE
2442
Kapowski, Kelly
87 99 100 87 88 -99
1254
Slater, A.C.
90 100 -99
8742
Morris, Zack
77 65 50 80 66 -99
结果:
Welcome to the automated grade book program. Version 2.0
Enter Student data filename:grades.txt
Name ID Average Grade Scores
Kapowski, Kelly 2442 92.2 A 87 99 100 87 88
Morris, Zack 8742 67.6 D 77 65 50 80 66
Slater, A.C. 1254 95.0 A 90 100
代码:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_NAME 50
#define MAX_SCORES 20
#define MAX_FILE_NAME 100
typedef struct {
char name[MAX_NAME];
int id;
double scores[MAX_SCORES];
int num_scores;
} student_t;
double student_average (student_t student);
FILE * get_data_file();
void get_data(student_t students[], int num_students, FILE *input_file);
void sort_student_array(student_t students[], int num_students);
int find_index_of_next(const student_t students[], int num_elements, int start_index);
void display_data(const student_t students[], int num_elements);
int main() {
student_t *students;
FILE *input_file;
int num_students;
input_file = get_data_file();
//Get the number of students in the data file
fscanf (input_file, "%d", &num_students);
//Dynamically allocate the student array
students = (student_t *)calloc(num_students, sizeof(student_t));
// Get the student data
get_data(students, num_students, input_file);
// Sort the array alphabetically
sort_student_array(students, num_students);
// Display the student data
display_data(students, num_students);
// Free the space allocated to the array
free(students);
return 0;
}
//For each of the student's scores, divide the total points by the number of scores
double student_average (student_t student) {
double average;
double total;
int count;
for (count = 0; count < student.num_scores; count++)
total += student.scores[count];
average = total / student.num_scores;
return average;
}
//Read in the data file and make sure it is valid
FILE * get_data_file() {
int valid = 0;
char file_name[MAX_FILE_NAME];
FILE *in_file;
printf("Welcome to the automated grade book program. Version 2.0\n");
do {
printf ("Enter student data filename:");
scanf ("%s", file_name);
in_file = fopen (file_name, "r");
if (in_file != NULL){
valid = 1;
} else {
printf ("Unable to open file %s. Try again.\n", file_name);
}
} while (!valid);
return in_file;
}
//Read data for each student
void get_data(student_t students[], int num_students, FILE *input_file) {
int count;
int count2;
student_t student;
double value;
for (count = 0; count < num_students; count++) {
//Read the student id number
fscanf (input_file, "%d\n", &student.id);
//Read the student name
fgets (student.name, MAX_NAME, input_file);
//Remove the newline from the name
student.name[strlen(student.name)-1] = '\0';
//Read the student test scores
fscanf(input_file, "%lf", &value);
count2 = 0;
while (value != -99){
student.scores[count2] = value;
fscanf(input_file, "%lf", &value);
count2++;
}
//Store count2 as the number of test scores for the student
student.num_scores = count2;
//Store the student in the student array
students[count] = student;
}
}
//Sort the students alphabetically
void sort_student_array(student_t students[],int num_students) {
int count;
int index_of_first;
student_t temp;
for (count = 0; count < num_students - 1; count++) {
index_of_first = find_index_of_next(students, num_students, count);
if (index_of_first != count) {
temp = students[count];
students[count] = students[index_of_first];
students[index_of_first] = temp;
}
}
}
// For each student in the list, Test if the student's name in count is
// before the student's name in index_of_first
int find_index_of_next(const student_t students[], int num_elements, int start_index) {
int count,
index_of_first = start_index;
for (count = start_index; count < num_elements; count++){
if (strcmp(students[count].name, students[index_of_first].name) < 0)
index_of_first = count;
}
return index_of_first;
}
//Displays the student data in proper format
void display_data(const student_t students[], int num_elements){
int count;
int index;
double average;
char grade;
printf ("\nName ID Average Grade Scores\n");
for(count = 0; count < num_elements; count++) {
printf ("%-20s", students[count].name);
printf (" %-4d", students[count].id);
average = student_average(students[count]);
printf (" %7.1lf", average);
if (average >= 90)
grade = 'A';
else if (average >= 80)
grade = 'B';
else if (average >= 70)
grade = 'C';
else if (average >= 60)
grade = 'D';
else
grade = 'F';
printf (" %5c", grade);
//Test if the student's name in count
//is before the student's name in index_of_first
for (index = 0; index < students[count].num_scores; index++)
printf (" %3.0lf", students[count].scores[index]);
printf ("\n");
}
}
如果有人可以告诉我错误的位置和可能的解决方案,我将非常感激。
我现在得到的结果是:
Welcome to the automated grade book program. Version 2.0
Enter Student data filename:grades.txt
它只是停下来,在这里什么都不做。
答案 0 :(得分:0)
您的输入文件格式错误。我的意思是,首先你要读取学生人数,然后在你的循环中,你想得到身份证,姓名和成绩。但是您的输入文件最初没有学生编号行,而是具有“ID,NAME,GRADE”行。像这样更改grade.txt文件将解决问题:
3
2442
Kapowski, Kelly
87 99 100 87 88 -99
1254
Slater, A.C.
90 100 -99
8742
Morris, Zack
77 65 50 80 66 -99
答案 1 :(得分:0)
如果你检查scanf调用的返回值,你可能很快就会解决问题。 scanf
返回成功转换的项目数,因此应为
if (scanf ("%s", ...) == 1) {
/* OK */
} else {
/* Problem. */
}
...
if (fscanf (input_file, "%lf", &value) == 1) {
/* OK */
} else {
/* Problem. */
}