Pointers and Arrays in C

From: Terence (findty_at_hotmail.com)
Date: 10/31/03 

Date: Thu, 30 Oct 2003 23:34:07 GMT

I usually program in Java, so I am a bit confused about usint pointers in C.
I would really appreciate if someone can help me.

Case 1:
======

// Is this function no good? Since str is a variable created on stack,
// I am assuming it will be deallocated immedately after the function returns,
// right??
char * generateString()
{
     char str[100] = "abc";
     return str;
}

Case 2:
=====

// str is a pointer pointing to a literal
// Can I use str just like other char arrays?
// How are memory allocated for literals and when are they deallocated??
void main()
{
      char * str;
      str = "abc";
}

Case 3:
=====

// Similar to case 2 except the literal is returned from a function
// Again, can I use str for anything? When is it deleted from memory??
void main()
{
      char * str;
      str = generateString();
}

char * generateString()
{
     return "abc";
}

Case 4:
=====

// assigning dynamically allocated array to pointer
void main()
{
      char * str;
      str = generateString();
      ...
      delete str; // I have to delete str at the end, Right?
}

char * generateString()
{
     char * charArray = new char[20];
     strcpy(charArray, "abc");
     return charArray;
}

Case 5:
=====

// str points to a char array created in a C library function
// How was this char array allocated? When will it be deallocated?
// Do I have to delete it explicitly??
void main()
{
      char line[20] = "abc#def";
      char * str;

      str = strtok(line, "#");

     delete str; // is this necessary?
     // can I modify the content of the array??
}

Relevant Pages

  • Pointers and Arrays in C
    ... Since str is a variable created on stack, ... void main ... // assigning dynamically allocated array to pointer ... // str points to a char array created in a C library function ...
    (comp.lang.cpp)
  • Pointers and Arrays in C??
    ... Since str is a variable created on stack, ... void main ... // assigning dynamically allocated array to pointer ... // str points to a char array created in a C library function ...
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  • Re: How to transfer an address value without using pointers
    ... void send; ... void send(char *str) ... Exactly the code above gives you a segmentation fault? ... pointer to an array with automatic storage duration. ...
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  • Re: How to transfer an address value without using pointers
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  • Re: Random String
    ... void RH_Random(unsigned char *str, size_t len) ... As long as it is a char array yes. ... Are you ever going to initialize something else to a string? ...
    (comp.lang.c)