I have a structure:
struct mystruct
{
开发者_Go百科 int* pointer;
};
structure mystruct* struct_inst;
Now I want to change the value pointed to by struct_inst->pointer
. How can I do that?
EDIT
I didn't write it, but pointer
already points to an area of memory allocated with malloc
.
As with any pointer. To change the address it points to:
struct_inst->pointer = &var;
To change the value at the address to which it points:
*(struct_inst->pointer) = var;
You are creating a pointer of type mystruct, I think perhaps you didn't want a pointer:
int x;
struct mystruct mystruct_inst;
mystruct_inst.pointer = &x;
*mystruct_inst.pointer = 33;
Of if you need a mystruct pointer on the heap instead:
int x;
struct mystruct *mystruct_inst = malloc(sizeof(struct mystruct));
mystruct_inst->pointer = malloc(sizeof(int));
*(mystruct_inst->pointer) = 33;
/*Sometime later*/
free(mystruct_inst->pointer);
free(mystruct_inst);
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