Strings1

Strings1

• 1.
  CS111 Lab Strings Instructor: MichaelGordon
• 2.
  The String class A class can be thought of as new type of variable that you can create.  C++ is also called “C with classes”  We’ve used one kind of class already: the string class, which is not in C.  string and its functions are built into C++.  C had C-strings, which can be found in the cstring library.
• 3.
  Strings  The internalconstruction of a string (or cstring) is really an array of characters.  The first character of string s is s[0].  string s = “Hello”; cout<<s[4]; //prints the letter o  To find the length of a string s we can use the functions .length() or .size()  int x = s.length(); gives x the value of the size of the string s (in this case, 5).
• 4.
  Strings  To “concatenate”two strings s1 and s2:  string s3 = s1 + s2;  string s1 = “race”;  string s2 = “car”;  string s3 = s1 + s2;  cout<<s3; //prints racecar
• 5.
  String examples string first,last, name; cout<<"Enter your first name:"; cin>>first; cout<<"Enter your last name:"; cin>>last; cout<<"Hi, "+first+" "+last; //concatenation
• 6.
  getline()  cin readsthe typed string only until the first whitespace.  If you want the whole string including those whitespaces, you can use:  getline(cin, stringname);  cout<<“Enter your name:”;  getline(cin, fullname);  Use fullname instead of first and last.
• 7.
  “dot” functions  Withstrings we start dealing with a new kind of function call. These functions operate on a specific “object” (an instance of a class).  We write the object name (e.g. the variable name of the string) followed by period and the function call (no space before or after the period).
• 8.
  More functions  s1.find(strings2) – returns the index of the beginning of s2 in s1.  s1 = “hello”;  s1.find(“lo”) – returns 3  s1.insert(int i, string s2) – inserts s2 into s1 at index I  s1.at(int i) – returns the character at index i in string s1