a little problem

[nenoviciss]

i have a problem
here is the code:


#include "stdafx.h"
#include <iostream>
using namespace std;

int main()
{ char *a,*b;
int x;
b = "test1234567890123";
a=new char [10];
cin>>x;
memcpy(a,&b[x],10);
cout<<a;

return 1;

}
for x=0 this code returns:test123456(and some other funny symbols)
how can i return only :test123456

[jsmith]

Aside from having many dangerous buffer overrun problems...

You have to null terminate the string. Make the a array 11 characters wide and set the last one to '\0'.

[nenoviciss]

thank you... if you can be more explicit about the"many dangerous buffer overrun problems" i will be even more thankful:)

[jsmith]

If the user enters a number greater than strlen(b) - 10 your memcpy will read beyond the end of the "b" string.

[nenoviciss]

and what function would you recomand me for copy a nomber of char from one string to another?

[jsmith]

I personally would use STL strings instead.

#include <algorithm>
#include <iostream>
#include <string>

using namespace std;

int main() {
    static const string b( "test1234567890123" );
    size_t x;
    cin >> x;
    cout << b.substr( std::min( x, b.length() - 1U ),
        std::min( 10U, b.length() - x ) ) << endl;
}