修改學生結構數組數組中的元素c

Question

我有這個到目前爲止，我需要幫助來修改它自己的學生信息。我嘗試了幾種方法，我似乎無法弄清楚。

#include <stdio.h> 

struct student 
{ 
    int id; 
    char name[50]; 
    int age; 
    char dept[10]; 
    float grade; 
}; 

int main() 
{ 
    struct student s[10]; 

    int i; 

    printf("Enter Student Information:\n"); 

    for (i=0; i<10; i++) 
    { 
     s[i].id = i+1; 
     printf("\nFor ID number %d\n",s[i].id); 
     printf("Enter name: "); scanf("%s",s[i].name); 
     printf("Enter age: "); scanf("%d", &s[i].age); 
     printf("Enter department: "); scanf("%s", s[i].dept); 
     printf("Enter grade: "); scanf("%f",&s[i].grade); 
     printf("\n"); 
    } 

    return 0; 
} 

Answer 1

可能有點過了頂你想要的東西，但誰的票：

#include <stdio.h> 
#include <string.h> 

struct student { 
    int id; 
    char name[50]; 
    int age; 
    char dept[10]; 
    float grade; 
}; 

void print_student(struct student * students, size_t num_students, int id); 
void set_student_by_id(struct student * students, size_t num_students, 
         int id, struct student * new_info); 


int main(void) { 
    struct student students[5] = { 
     {100, "John", 17, "Physics", 3.2}, 
     {101, "Emily", 16, "Maths", 3.8}, 
     {102, "Peter", 18, "Drama", 2.1}, 
     {103, "Doug", 16, "English", 3.3}, 
     {104, "Sara", 17, "Astronaut", 3.9} 
    }; 

    size_t num_students = sizeof(students)/sizeof(students[0]); 

    /* Print details for student 101 before change */ 

    print_student(students, num_students, 101); 

    /* Change details for student 101 */ 

    struct student new_info = {-1, "Emily", 17, "Farming", 3.9}; 
    set_student_by_id(students, num_students, 101, &new_info); 

    /* Print details for student 101 after change */ 

    print_student(students, num_students, 101); 

    /* Attempt to print details for imaginary student 105 */ 

    print_student(students, num_students, 105); 

    return 0; 
} 


/* 
* Prints the details for a selected student. 
* 
* Arguments: 
* students - pointer to an array of students 
* num_students - number of students in the array 
* id - ID of the student to print 
*/ 

void print_student(struct student * students, size_t num_students, int id) { 
    size_t i; 
    for (i = 0; i < num_students; ++i) { 

     /* Search array for student by ID */ 

     if (students[i].id == id) { 
      printf("Info for student ID %d:\n", id); 
      printf(" Name: %s\n", students[i].name); 
      printf(" Age: %d\n", students[i].age); 
      printf(" Dept: %s\n", students[i].dept); 
      printf(" Grade: %.1f\n", students[i].grade); 

      break; 
     } 
    } 

    if (i == num_students) { 
     printf("Student ID %d not found.\n", id); 
    } 
} 


/* 
* Changes the details for a selected student. 
* 
* Arguments: 
* students - pointer to an array of students 
* num_students - number of students in the array 
* id - ID of the student to change 
* new_info - pointer to struct student containing new details 
*/ 

void set_student_by_id(struct student * students, size_t num_students, 
         int id, struct student * new_info) { 
    size_t i; 
    for (i = 0; i < num_students; ++i) { 

     /* Search array for student by ID */ 

     if (students[i].id == id) { 

      /* Change everything except the ID */ 

      strcpy(students[i].name, new_info->name); 
      strcpy(students[i].dept, new_info->dept); 
      students[i].age = new_info->age; 
      students[i].grade = new_info->grade; 

      break; 
     } 
    } 

    if (i == num_students) { 
     printf("Student ID %d not found.\n", id); 
    } 
} 

輸出：

paul@local:~/src/c/scratch$ ./student 
Info for student ID 101: 
    Name: Emily 
    Age: 16 
    Dept: Maths 
    Grade: 3.8 
Info for student ID 101: 
    Name: Emily 
    Age: 17 
    Dept: Farming 
    Grade: 3.9 
Student ID 105 not found. 
paul@local:~/src/c/scratch$