C结构数组(抛出异常) [英] C array of structure (exception thrown)

问题描述

我创建了一个结构为Human的数组，该数组由 char * name 组成.

I have created an array of structure Human which consists of char *name.

我使用这样的功能:

Human *createHuman(char *name){
    Human *h = malloc(sizeof(Human));
    h->name = strdup(name);
    return h;
}

我已经测试了此功能，它可以正常工作，但是当我像这样使用它时，我的问题就开始了:

I have tested this function, it works perfectly, but my problem starts when i use it like this:

void gen_Humans(Human array[MAX], int n){
    //n == max;
    for (int i = 0; i<n; i++){
        char *name = gen_name_function_used_before_WORKING();
        array[i] = *createHuman(*name);
    }
    …
}

正如我说的，如果我产生一个人，那就很好了.我调试了代码，直到到达 strdup(name)的地步时，它才给我:

As I said, if I generate one human it works just fine. I debugged my code and when I got to the point of strdup(name) it threw me this:

my error: Exception thrown at 0x53DCF6E0 (ucrtbased.dll) in project.exe:
0xC0000005: Access violation reading location 0x00000070.

我正在使用VS 2017 Enterprise.

I am using VS 2017 Enterprise.

推荐答案

添加到@MortizSchmidt的答案:

Adding to @MortizSchmidt's answer:

• 您没有检查 malloc()的结果.即使失败的机会很小，您也应该这样做.
• 您正在泄漏内存-因为您永远不会释放 malloc()的内存，也不会将指针放在任何地方.请记住，C与Java不一样-赋值不是引用的赋值.
• 请注意，函数签名中的 MAX 指示符没有任何作用.该参数是您可以通过任何方式编写的int *类型: int *数组， int数组[] 或 int数组[MAX] .

• You are not checking the results of malloc(). You should do so, even if the chances of failure are small.
• You are leaking memory - since you never free the malloc()ed memory nor do you keep the pointer anywhere. Remember C is not like Java - assignment is not an assignment of a reference.
• Note that the MAX indicator in the function signature doesn't have any effect. The parameter is an int* any way you write it: int* array, int array[] or int array[MAX].

实际上，为什么还要分配Human结构而不是仅仅为字符串分配空间?

Actually, why even allocate the Human structure rather than just space for the string?

struct Human createHuman(char *name){
    if (name == NULL) {
        struct Human h = { NULL };
        return h;
    }
    struct Human h = { strdup(name) };
    if (h.name == NULL) { /* handle error here */ }
    return h;
}

void gen_Humans(Human array[MAX], int n){
    for (int i = 0; i < n; i++) {
        char *name = gen_name_function_used_before_WORKING();
        array[i] = createHuman(name);
    }
    …
}

这具有在将 name 设置为0之后将 Human 中的所有字段初始化的额外好处.

This has the added benefit of initializing all fields in Human after name to 0.

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