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carraysdynamic-arrays

Can I write a variable sized array with this code?

Can I write a variable sized array using the following code?

I have executed it on Fedora. I used a pointer a and integer b to create the array, so can I say that this array is a dynamic array?

main()
{
    int * const a;  
    int b;
    a[b];     
    b=5;
    int i;
    for(i=0;i<5;i++)
    {
     printf("%d\n",a[i]);
    }
}
Solution

  • No, you can't create variable-length array using this code. When you use

    int b;

    b can have any value. It can be 0, 4294967295, or any other number. Then, when you use

    a[b];

    a can have any random length each time use execute the program.

    Next thing: a will not change it's size when you change b value:

    int b = 5;
int a[b];
b = 6;
// Length of `a` is still 5.


    If you want to change size of array after it's been created, you should read about malloc() and realloc() functions and use them.