Dynamic array in Stack?

by

Here’s your combination answer of all these other ones:

Your code right now is not standard C++. It is standard C99. This is because C99 allows you to declare arrays dynamically that way. To clarify, this is also standard C99:

#include <stdio.h>

int main()
{
    int x = 0;

    scanf("%d", &x);

    char pz[x]; 
}

This is not standard anything:

#include <iostream>

int main()
{
    int x = 0;
    std::cin >> x;
    char pz[x]; 
}

It cannot be standard C++ because that required constant array sizes, and it cannot be standard C because C does not have std::cin (or namespaces, or classes, etc…)

To make it standard C++, do this:

int main()
{
    const int x = 12; // x is 12 now and forever...
    char pz[x]; // ...therefore it can be used here
}

If you want a dynamic array, you can do this:

#include <iostream>

int main()
{
    int x = 0;
    std::cin >> x;

    char *pz = new char[x];

    delete [] pz;
}

But you should do this:

#include <iostream>
#include <vector>

int main()
{
    int x = 0;
    std::cin >> x;

    std::vector<char> pz(x);
}

More Related Contents:

  1. Questions regarding constructors
  2. How would I implement Arrays into this code
  3. Invalid solution for code challenge with operator restrictions
  4. What does “dereferencing” a pointer mean?
  5. Why do I need strand per connection when using boost::asio?
  6. Why are Standard iterator ranges [begin, end) instead of [begin, end]?
  7. Qt Linker Error: “undefined reference to vtable” [duplicate]
  8. Displaying the #include hierarchy for a C++ file in Visual Studio
  9. Rounding up to the nearest multiple of a number
  10. Using C++ library in C code
  11. Encode/Decode URLs in C++ [closed]
  12. How to return a std::string.c_str()
  13. GDB complaining about missing raise.c
  14. placement new and delete
  15. Template template parameters
  16. How to specify preference of library path?
  17. how-to initialize ‘const std::vector’ like a c array
  18. Dereferencing an invalid pointer, then taking the address of the result
  19. why reference size is always 4 bytes – c++
  20. Why the sizeof(bool) is not defined to be one, by the Standard itself?
  21. How to use graphics.h in codeblocks?
  22. Does boost have a datatype for set operations that is simpler than the STL?
  23. Using `std::function` to call non-void function
  24. Using std::string_view with api that expects null-terminated string
  25. For loop prints an extra comma
  26. Duplicate const qualifier allowed in C but not in C++?
  27. Differences between running an executable with Visual Studio debugger vs without debugger
  28. Seeking code stub generator (from header files) [closed]
  29. Find available network interfaces in C/C++? [closed]
  30. Is there a case where including the same header twice is actually helpful?

Leave a Comment