C static main return value of 0 在使用 free(someUnrelatedPointer) 之后改变了吗？

Question

我正在学习 C 并且我这样做了(下面的代码，我不明白为什么我得到的程序返回值类似于 -1073740940 而它应该是 0

#include <stdio.h>
#include <stdlib.h> //For using malloc;


struct Vertex{
    int x;
    int y;
    int z;
};

int main(){
    int ret = 0;
    struct Vertex myVertex;
    struct Vertex *myVertexPtr = malloc(sizeof(*myVertexPtr));


    myVertexPtr = &myVertex;

    myVertex.x = 1;
    myVertex.y = 2;
    myVertex.z = 3;

    printf("%d\n", myVertexPtr->x);
    printf("%d\n", myVertexPtr->y);
    printf("%d\n", myVertexPtr->z);

    getchar();

    free(myVertexPtr); //When this line is included I get the strange program return    value (And, "This program has stopped working properly windows error")
                   //When this line is not included it returns fine, but I'm under the impression it is good practice to free pointers

    return 0;
}

我正在使用 MinGW GCC 编译

Answer 1

这一行:

myVertexPtr = &myVertex;

覆盖 malloc() 返回的指针，因此您将错误的值传递给 free()，从而导致错误。它还会导致内存泄漏，这在运行时间更长的程序中将是一个问题。不要这样做!

它应该简单地被删除，如果你想在堆上使用一个顶点，这样做:

myVertexPtr = malloc(sizeof *myVertexPtr);
myVertexPtr->x = 1;
myVertexPtr->y = 2;
myVertexPtr->z = 3;

如果你想有一个单独的指针指向堆栈上的顶点，删除 malloc():

myVertexPtr = &myVertex;