將用戶輸入值分配給分配的內存

該程序背後的思想是爲學生信息聲明一個數據結構，然後讓用戶將輸入信息輸入數據結構的每個字段中，以便輸入數量的學生。我的問題是程序停止工作，當我輸入名字。哪裏不對？感謝您的時間。將用戶輸入值分配給分配的內存

//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; 
}

來源

2014-11-14 sourcecodedysfunction

我已經調整了scanf_s的，但該計劃似乎仍在崩潰。我不認爲這是正確的處理。如果我聲明一個類型爲struct student的數組並將其數組大小設置爲用戶輸入，會怎麼樣？ – sourcecodedysfunction

你應該做

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

讀頭名。 ptr+i會給你student結構。您想要將數據存儲在結構成員中。

更改您的其他scanf s爲此。

來源

2014-11-14 04:43:11 Rohan

不，缺少尺寸參數。「fscanf_s函數等同於fscanf，只是c，s和[轉換說明符適用於一對參數...」 – chux

你可以在你的scanf（）的使用

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

等的結構成員的其餘部分。

來源

2014-11-14 04:43:40 Gopi

變化scanf_s到scanf並更改該塊如下：

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);

來源

2014-11-14 05:42:45

將用戶輸入值分配給分配的內存

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