Question

I’ve this simple program and need to know on which basis should I choose the have for the variable (howToPredectThisNumber) (i.e. the size of the char* string).

And Which is best to choose in this case, char[] or char*??

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

typedef struct
{
    char* name;
}Emp;

void init(Emp** emp)
{
    int howToPredectThisNumber = 50;
    *emp = malloc(sizeof(Emp));
    (*emp)->name = NULL;
    (*emp)->name = calloc(howToPredectThisNumber, sizeof(char*));
}

void release(Emp** emp)
{
    free((*emp)->name);
    free(*emp);
}

void setName(Emp* emp, char* newName)
{
    strcpy(emp->name, newName);
}
char* getName(Emp* emp)
{
    return emp->name;
}

int main(void)
{
    Emp* emp;
    init(&emp);
    setName(emp, "Muhammad            Abdullah");
    printf("%s", getName(emp));
    release(&emp);

    return 0;
}

Answer 1

I guess you should delay that deduction until you know what you want to copy:

void setName(Emp* emp, char* newName)
{ 
    free(emp->name);
    emp->name = malloc( strlen( newName ) + 1 );
    strcpy(emp->name, newName);
}