Dynamic memory allocation | Unable to write on location

November 15, 2021

NOTE: Sorry if this is duplicate but i haven’t found any case which is similar to mine.

I am working on a C language project and I am not good at this. I am a very noob at dynamic memory allocation. So the issue I am facing is that when I create an instance of a structure which is given below

typedef struct temp_ {
    Household data;
    struct temp_ * next;
}Node, *NodePtr;

by this way it or many others I have tried so far

NodePtr makeNode(Household num){
    NodePtr ptr = (NodePtr) malloc(sizeof(NodePtr));
    ptr->data = num;
    return ptr;
}

So I get different types of errors that I can not understand.
If anyone can help it will be a great pleasure.

>Solution :

Never hide pointers behing typedefs. It is extremely error prone. In your code you do not allocate enough memory, thus segfault.
Use objects not types in sizeof

typedef struct temp_ {
    Household data;
    struct temp_ * next;
}Node;

Node *makeNode(Household num){
    Node *ptr = malloc(sizeof(*ptr));
    if(ptr) ptr->data = num;
    return ptr;
}