Webvoid GetMemory (char **p,int num) { //p，指向指针的指针，*p，p指向的指针 (即str)，**p，最终的对象，str指向的单元 *p= (char *)malloc (num); //申请空间首地址付给传入的被p指向的指针，即str } int main () { char *str=NULL; GetMemory (&str,100); //传入指针变量本身的地址 strcpy (str,"hello"); WebMay 14, 2024 · GetMemory ( str ); //GetMemory (&str)编译出错，将一个指针地址值传递给一级指针。. strcpy ( str, “hello world” ); printf ( “%s”，str ); } 这个一个考验对指针理解 …
C/C++ Frequent Pointer Mistakes Algorithms, Blockchain and …
WebJun 11, 2024 · 错误方式申请内存 void GetMemory(char *p, int num) { p = (char *)malloc(sizeof(char) * num); } void Test(void) { char *str = NULL; GetMemory(str, 100); // str 仍然为 NULL strcpy(str, "hello"); // 运行错误 } Paste_Image.png 毛病出在函数 GetMemory中。 编译器总是要为函数的每个参数制作临时副本，指针参数 p 的副本是 … WebApr 18, 2014 · char* GetMemory(int num) { char *p = (char*)malloc(sizeof(char) * num); // allocate space on heap return p; } void Test() { char *str = NULL; str = GetMemory(100); … flat bottomed trainers
Getmemory函数详解--内存操作的理解_p = (char …
WebDec 13, 2024 · 1，调用GetMemory ( str )后， str并未产生变化，依然是NULL.只是改变的str的一个拷贝的内存的变化. 2，strcpy ( str, “hello world” );程序运行到这将产生错误。. … WebSep 29, 2024 · void GetMemory (char* p) { p = (char*)malloc (100); } void test () { char* str = NULL; GetMemory (str); strcpy (str, "hello world"); printf (str); free (str); str = NULL; } Program error. Call by value: if str value is not changed, it is still a null pointer that will not be modified. You can use secondary pointer to receive str address. WebGetMemory ( &str, 100 ); strcpy ( str, "hello" ); printf ( str ); } 1 [Run correctly, but there are memory leaks] title three topics to avoid a problem, the parameter is a pointer passed … checkmarx failed to send queries and sources