I wanna create an array whose size would be determined by a variable, but i when i write the following, i got an error

int main ()
{
int a;
std::cin >> a;
int intArray [a];

return 0;
}

the error is "an constant expected".

The error is correct -- you can't do that in todays C++. Have you been introduced to new/delete?

you can't use a variable define a array's size
#include <iostream.h>
int main ()
{
int a;
cin >> a;
int *intArray;
intArray=new int(a);

return 0;
}

Thanks for the answers, i can solve my problem now. But i got another question regarding arrays. I tried to make an array of c-style strings with the following code, but got an error:


the error message is: "the compiler is unable to convert from the type char (*) [30] to the type char **."

Why is it so and how can i solve it? :-|

Multidimensional arrays are actually arrays of arrays, so you need to allocate memory to reflect that:
Then to free them:
The nice thing is that you can index an array allocated like this with the subscript operator:
Not all multidimensional allocation schemes allow you to do that.