Posts tagged pointers
char *p, *q; p = malloc(1); free(p); q = p; // lvalue conversion Is the last lvalue conversion (= p;) Undefined Behavior or not? We didn't take the address of the local p. C11::6.3.2.1...
I've heard that in modern C++, smart pointers are preferred to raw pointers for ownership (the so-called RAII principle, as I understand it). This makes sense, and since then I've always used them...
So I just started learning how to use file-streams in C & decided to attempt a question which is to do with library management in C, however I am currently encountering some problems and feel l...
Let's consider the following code: const char a[][4] = {"aa", "aaa"}; const char *b[] = {"bb", "bbb"}; const char *const c[] = {"cc", "ccc"}; For shared libraries, both b and c arrays require...
When writing any form of custom function such as this: void func (int* a, int* b) Should I add code to check if a and b are null pointers or not? if(a == NULL) /* error handling */ When po...
What does ptr() mean in this code? #include<stdio.h> #include<stdlib.h> void PrintHello() { printf("Hello\n"); } int Add(int a, int b) { return a+b; } int main...
I've created a function that calls scanf passing a void pointer as argument: void read(const char *format, void *p) { scanf(format, p); } And tested it with different types: int n; read...
Background This is kind of a subquestion to How to properly use malloc? When allocating, there are basically two common ways of using the sizeof operator: int *p; p = malloc(n * sizeof *p); /...
Consider this code: #include <stdio.h> int main(void) { static void *ptr; if(ptr == NULL) puts("It's NULL!"); } I wonder if this is guaranteed to print "It's NULL!" I know ...
When reading posts at programming sites such as this one, I frequently encounter people saying things like: "There is no pass-by-reference in C, everything is passed by value." People claiming su...
Can anyone help me, I'm currently learning pointers, this is the code I wrote to try and insert a node at the beginning of the list. However at the part where I included the comment of "error at th...
Question: There is a list of integers in an array (3,2,1,5,6,4), sort this list in both ASCENDING & DESCENDING order. Create a sort function. #include<stdio.h> #include<stdlib.h> ...
Hey, regarding a question on returning pointers as functions, why does my code produce this error & won't print out the sum = 6? #include<stdio.h> #include<stdlib.h> int *A...
#include<stdio.h> struct Node{ int data; struct Node* next; }; Here I used an asterisk after Node. What is it used for? What if I don't put any asterisk after Node (both Node...
I have heard that it is undefined behaviour to make a pointer point outside boundaries of an array even without dereferencing it. Can that really be true? Consider this code: int main(void) { ...
