int main( void )
{
    int n = 10 ;
    for(int j = 0; j < n; j++){ 
        // do something useful. . .
    }
    cout << j <<endl;

    return 0 ;
}

In function 'int main()':
Line 7: error: name lookup of 'j' changed for new ISO 'for' scoping
compilation terminated due to -Wfatal-errors.