Difference between new and malloc( )

In this post, we will understand the difference between ‘new’ and ‘malloc’.

new

• It is present in C++, Java, and C#.

• It is an operator that can be used to call the constructor of the object.

• It can be overloaded.

• If it fails, an exception is thrown.

• It doesn’t need the ‘sizeof’ operator.

• It doesn’t reallocate memory.

• It can initialize an object when allocating memory for it.

• The memory allocated by ‘new’ operator can be de-allocated using ‘delete’ operator.

• It reduces the execution time of the application.

Example

#include<iostream>
using namespace std;
int main(){
   int *val = new int(10);
   cout << *val;
   getchar();
   return 0;
}

malloc

• This is present in C language.

• It is a function that can’t be overloaded.

• When ‘malloc’ fails, it returns NULL.

• It requires the ‘sizeof’ operator to know how much memory has to be allotted.

• It can’t call a constructor.

• Memory can’t be initialized using this function.

• The memory allocated using malloc can be deallocated using free function.

• Memory allocated by malloc method can be reallocated using realloc method.

• It requires more time to execute applications.

Following is the example of malloc in C language −

Example

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main () {
   char *str;
   /* Initial memory allocation */
   str = (char *) malloc(5);
   strcpy(str, "amit");
   printf("String = %s, Address = %u
", str, str);
}