Question

该计划背后的想法是宣布学生信息的数据结构，然后将用户输入信息输入到输入数量的学生的数据结构的每个字段中。我的问题是当我输入名字时程序停止工作。怎么了？谢谢你的时间。

//Inclusion of necessary header files
#include <stdio.h>
#include <stdlib.h>

//Data structure declaration
struct student{
char firstName[20];
char lastName[20];
char id[10];
char gender;
int age;
double gpa;
};

//Function prototypes
void readStudentsInformation(struct student *, int size); 
void outputStudents(struct student *, int size);
double averageGPA(struct student *, int size);
void sortByLastName(struct student *, int size);
void sortByGPA(struct student *, int size);


//Entry point
int main()
{
    //Variable delcaration
    int size;
    struct student *ptr;
    //Input prompt and function
    printf("How many students?\n");
    scanf_s("%d", &size);

    //Allocation memory for struct student times the number of students and assigning it to a struct student pointer for external function modification
    ptr = (struct student*)malloc(sizeof(struct student)*size);

    //readStudentsInformation Function call
    readStudentsInformation(ptr, size);

    //Exit sequence
    return 0;
}

//This functions reads the information for all the students from the keyboard, taking the class size through the pointer method and struct student from main
void readStudentsInformation(struct student *ptr, int size) 
{
    //For loop controller declaration
    int i;
    //Function message
    printf("Student Information Form\n");
    //This for loop increments the "index" of each students info location where user input is stored
    for(i=0;i<size;i++)
    {
        //Each field has it's appropriate input limit
        printf("Please enter Student %d's First Name(20 characters).\n", i+1);
        scanf_s("%20s", ptr[i].firstName);
        printf("Please enter Student %d's Last Name(20 characters).\n", i+1);       
        scanf_s("%20s", ptr[i].lastName);                                   
        printf("Please enter Student %d's ID(10 characters).\n",i+1);               
        scanf_s("%10s", ptr[i].id);
        printf("Please enter Student %d's gender(M/F).\n",i+1);
        scanf_s("%c", ptr[i].gender);
        printf("Please enter Student %d's age.\n",i+1);
        scanf_s("%3d", ptr[i].age);   //Only 3 digits can be put in at a time
        printf("Please enter Student %d's GPA.\n", i+1);
        scanf_s("%.1lf", ptr[i].gpa);   //From the lab it can be seen that no more than one decimal place is featured, so the same is done here
    }

    //Exit to main
    return;
}

Answer 1

你应该做

scanf_s("%20s", ptr[i].firstName);

阅读名字。 ptr+i将为您提供student结构。您希望将数据存储在结构成员中。

为此更改您的其他scanf。

Answer 2

您可以使用

scanf("%s",ptr[i].firstName);

对于scanf（）中的其他结构成员，

等等。

Answer 3

将scanf_s更改为scanf并更改此块，如下所示：

    scanf("%c", &ptr[i].gender);
    printf("Please enter Student %d's age.\n",i+1);
    scanf("%3d", &ptr[i].age);   //Only 3 digits can be put in at a time
    printf("Please enter Student %d's GPA.\n", i+1);
    scanf("%1lf", &ptr[i].gpa);

将用户输入值分配给已分配的内存

3 个答案: