CODEWITHSUNDEEP
c++string
Josep
Josep

Reputation: 162

How to 'NULL' a string in c++

I am new in C++ and now I am learning how cin and cout works. The case is, as you can see in the code below I create a string, and a char * in order to compare the C way to read a string and the C++ way. In C++, it makes sense that if I create a string then I worry about to set this string to NULL?

#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <string>
#define SIZE 10

using namespace std;
int main () {
  cout << "Write Something: \n";
  string f1;
  char *p;
  p = (char *) malloc(SIZE); // This is how I will use it in c
  getline(cin, f1);
  cout << "Write Something else: \n";
  scanf("%s", p);
  cout << f1 << "1\t";
  printf("%s2\n", p);
  free(p);
  p = NULL; // After the pointer has been freed, we set it to NULL
  cout << "p freed\t";
  f1.clear();
  cout << "f1 deleted\t";
  return 0;
}

Upvotes: 0

Views: 223

Answers (2)

JCWasmx86
JCWasmx86

Reputation: 3583

No, you don't have to even clear f1, as the RAII will automatically cleanup, when the function returns.

Upvotes: 1

Remy Lebeau
Remy Lebeau

Reputation: 597941

You don't have to worry about setting a std::string object to NULL.

And you don't have to clear() it if it is just going to go out of scope right afterwards. Its destructor will handle freeing any memory used for the character data for you.

Upvotes: 2

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