Thread: Memory allocation at run time

  1. #1
    Registered User
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    Memory allocation at run time

    Can someone clarify what's memory allocation at run time ?

    When I need to write a program I write it on editor and save it. when i compile/run program. compiler allocate memory. if there is error in code compiler show error. if there is no error then compiler show result

    Code:
    #include<stdio.h>#include<stdlib.h>
     
    int main ()
    {
      int *x = malloc(sizeof(*x)); // allocate dynamic memory for x
      *x = 1;  
      printf( "x = %d\n", *x);
    
    
      return 0;
       
    }
    In a program dynamic memory will allocate for pointer when i compile and run the code

    What's term " Memory allocation at run time " in code development?

  2. #2
    and the hat of int overfl Salem's Avatar
    Join Date
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    Well you're doing dynamic allocation (which is also the definition of "at runtime") when you call malloc / calloc / realloc / free.

    Your code should be
    Code:
    #include<stdio.h>
    #include<stdlib.h>
      
    int main ()
    {
      int *x = malloc(sizeof(*x)); // allocate dynamic memory for x
      if ( x != NULL ) { // always check, it might fail
        *x = 1;  
        printf( "x = %d\n", *x);
        free(x);  // always free when you're done.
      }
    
      return 0;   
    }
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

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