COP 3530 Data Structures & Algorithms Discussion Session 3

Outline  Input-output streams in C++  Floating point precision  File manipulation  Pointers in C  Vector class in C++  Strings in C and C++

About me  Eyup Serdar Ayaz   TA Office: E309  This week no office hours

Input and output streams in C++  Stream classes  Stream objects  Insertion ( >) operators

Floating point precision  default precision  scientific precision  fixed precision

File manipulation in C++  Include necessary header: fstream  Declare an file stream: ifstream or ofstream  Open the stream file  Check if the file is opened  Read from or write to the stream  Close the stream

File manipulation example

Pointers in C  Reference operator (&)  Dereference operator (*)  Types of pointers  Arrays as pointers  Pointer arithmetic  Pointers to pointers  Null pointer

Vector class in C++  An STL (Standard Template Library) container  An strict sequence container i.e. An array of variable size. Similar to ArrayList of Java  Defined as a template, type should be specified  Most useful functions:  operator[]  size  insert  erase  begin  end

A vector example

Strings in C  Strings are char arrays  Declared as char arrays or pointers  Ends with ‘\0’ or simply 0  String manipulation functions are defined in  Cannot be assigned directly other than declaration  Frequently used functions:  strcpy  strcmp  strcat  strlen

cstring example

String class in C++  Strings are objects  String manipulation functions are defined in  Can be directly assigned  Can be concatenated using + operator  Frequently used functions:  operator[] or at  size  copy  compare  substr  operator+= or append

C++ String example(Comparison)

References   cpp/io/readtextfile.html cpp/io/readtextfile.html   s/setprecision/ s/setprecision/ 