Dynamic Array

[achilleas11]

///////////// start code /////////////
#include<iostream>
#include<iomanip>

using namespace std;

int ReadSquareSize()
{
int x;
cout<<"Plhktrologhse to mege8os tou pinaka, akeraios 8etikos perittos apo 3 kai panw: ";
while(1)
{
cin>>x;
if(x>=3 && x%2==1)
{
return x;
}
else
{
cout<<"Plhktrologhse to mege8os tou pinaka, akeraios 8etikos perittos apo 3 kai panw: ";
}
}
cout<<endl;
}

int main()
{
int n = ReadSquareSize();
int square[n][n]; //----- error here -----
}

///////////////// end code /////////////////

This is a part from my code. What i cannot understand is why i get 6 errors in the error line. I have declared n from the previous line. Malloc is better to use? If so, can u post the corrected code lines?

[Colloid Snake]

You use 'int main' and you don't use any return statement.

Try putting return 0; below your array declaration.

Also, the error messages might help.

[Tomassus]

Hi there,

You can't daclare something like:

int x;
cin >> x;
int a[x];

It won't compile because x is unknown in the time of compilation. Values in brackets while declaring arrays have to be daclered before compilation.

U can try to declare 2-dimension array using new. Problem is that in C++ u can't declare 2-dimensional array directly.
Example u can remake for your code:

int **a = new int*[x];
for (int i = 0; i < x; ++i)
a[i] = new int[y];

I encourage you to learn about very nice funcion from STL library -> vectors. U can find a use for them in your example.

[sircool]

///////////// start code /////////////
#include<iostream>
#include<iomanip>

using namespace std;

int ReadSquareSize()
{
int x;
cout<<"Plhktrologhse to mege8os tou pinaka, akeraios 8etikos perittos apo 3 kai panw: ";
while(1)
{
cin>>x;
if(x>=3 && x%2==1)
{
return x;
}
else
{
cout<<"Plhktrologhse to mege8os tou pinaka, akeraios 8etikos perittos apo 3 kai panw: ";
}
}
cout<<endl;
}

int main()
{
int n = ReadSquareSize();
int square[n][n]; //----- error here -----
}

///////////////// end code /////////////////

This is a part from my code. What i cannot understand is why i get 6 errors in the error line. I have declared n from the previous line. Malloc is better to use? If so, can u post the corrected code lines?

if you use like that definitation
int square[n][n] that means you made a array static.So n must be const that does not matter you return a n value from any function.
i will make a dynamic aray declaration you can use

int **arary,row,colomn; // two asterix means you make two dimentional aray
than you will request memory (in C malloc, in C++ you can use new function)

array=new int*[row];
for(int a=0;a<row;a++) //row=n in your code
array[a]=new int[colomn]; //request a colomn*sizeof(int) memory for each row

merory management is like that and dynamic arrays can be like that

keep in touch