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[QUOTE="Adem, post: 3673968"]
HOWTO: const and pointer variants in C and C++ :

void test()
  {
    int               n = 1;    // n is non-const data of type int
    ++n;                        // ok

const  int        c = 2;    // c is const data of type int
 // ++c;                        // err

// Case1:
    int*              p1 = &n;  // p1 is a non-const ptr to non-const data
    ++p1;                       // ok
    *p1 += 3;                   // ok

// int*              px = &c;  // err

// Case2:
    int*   const      p2 = &n;  // p2 is a const ptr to non-const data
 // ++p2;                       // err
    *p2 += 3;                   // ok

// Case3:
    const  int*       p3 = &c;  // p3 is a non-const ptr to const data
    ++p3;                       // ok
 // *p3 += 3;                   // err

// Case4:
    const  int* const p4 = &c;  // p4 is a const ptr to const data
 // ++p4;                       // err
 // *p4 += 3;                   // err

// Case5:
    const  int* const p5 = &n;  // Similar to Case4 but here non-const n is treated as const data when accessed via p5
 // ++p5;                       // err
 // *p5 += 3;                   // err

// Case6:
    const  int *const p6 = &c;  // same as Case4
 // ++p6;                       // err
 // *p6 += 3;                   // err

// Case7:
    const  int *const p7 = &n;  // Same as Case5
 // ++p7;                       // err
 // *p7 += 3;                   // err

// const* int        p8 = &n;  // err
 // const* int        p9 = &c;  // err

// const  int const* pa = &n;  // err: duplicate 'const'
 // const  int const* pb = &c;  // err: duplicate 'const'
  }

For safety and speed you should use const whenever possible.
[/QUOTE]

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