Online Time 12/10

Topics

1. Assignment 11 review

Requested review questions

2. the reason that we do not have to use if(fin.eof()) break; in the case of while(fin>>variable)

3. question about data type. Like long int , unsigned int ,short int, signed int, what are the difference between them?

4. Usage of setw() (when to use left, right, where the number inputted actually is i.e. setw(9) for a string)

5. vectors

6. argument types (when to use int* or int array[] and differences)

7. For setprecision(), when should you use and not use fixed?

8. Practice problem #8
   
    The attached file contains a secret message.  You have to decode it.  
    The file contains ascii codes + the position of the char in the message.
    For example, if the secret message is "ABCD", then the file would contain 

    65
    67
    69
    71

    65 = 'A' + 0
    67 = 'B' + 1
    69 = 'C' + 2
    71 = 'D' + 3

    Decode the file


-----------------------------------
if(fin.eof()) break; 

while(fin>>variable)

while (!fin.eof())
{
   fin >> whatever
   getline(fin,buffer)
   if (fin.eof()) break;
...
// processing
}

while(fin>>variable)
{
}

if read operation fails (for example, EOF), then stream goes into an error state
ifstream is derived from istream

conversion operator

cin >> a >> b >> c;

int array[50];

vector<int> v;
v.push_back(5);
cout << v[5];
v[0] = 6;

constructor

a vector is a template
vector<int> is a class
vector<int> v;  v is an object

vector<int> w(v);

vector<int> x(10);