小编Ian*_*ing的帖子

在常规HTML中,您可以将多个字段POST到数组:

<input type="text" name="arr[]">
<input type="text" name="arr[]">
<input type="text" name="arr[]">
<input type="text" name="arr[]">

如何从WTForms获得此功能？基本上,我有一个用户的表单,然后单击小加号和减号按钮来添加或删除表单中的字段.

我在函数中delete的指针,然后我设置为.但是,在运行该函数后,不再设置,所以我必须再次设置它.aStudentdestroyStudent()aStudentnullptraStudentnullptrnullptr

#include <cstring>

using namespace std;

struct Student {
   char *     name;
   float      gpa;
};

Student * createStudent(const char name[], float gpa) {
    struct Student * student = new Student;
    student->name = (char*)malloc(strlen(name + 1)); //allocate only enough memory to fit the given name
    strcpy(student->name, name);
    student->gpa = gpa;

    return student;
}

bool destroyStudent(Student * aStudent) {
    if(aStudent) { //check whether this pointer is already null.
        free(aStudent->name);
        delete aStudent; // ******This …

#include <cstring>
using namespace std;

struct Product {
   char *     name;
   float      price;
};

int main() {
    Product * bread = new Product;
    bread->name = new char[6];
    bread->name = "bread";

    delete[] bread->name; //!!!THE ERROR OCCURS ON THIS LINE!!!
    delete bread;
}

给我以下错误:

*** Error in `./out': munmap_chunk(): invalid pointer: 0x0000000000400824 ***

我的问题是,是否有必要删除面包 - >名称,或者删除面包将为我处理.如果有必要删除bread-> name,为什么程序在我尝试时会崩溃？