Standard Library Classes string and vector

We learned that we can build a String (Array) class that is better than the C-style, char * strings (pointer-based arrays) that C++ absorbed from C.

• Classes built into C++
  • Available for anyone to use
  • string ; Similar to our String class
  • vector; Dynamically resizable array
• Redo our String and Array examples
  • Use string and vector
• Class string
  • Header $<$string$>$, namespace std
  • Can initialize string s1("hi");
  • Overloaded $«$; cout $«$ s1
  • Overloaded relational operators; == != $>=$ $>$ $<=$ $<$
  • Assignment operator =
  • Concatenation (overloaded +=)
  • Substring function substr
    • s1.substr(0, 14); ; Starts at location 0, gets 14 characters
    • S1.substr(15) ; Substring beginning at location 15
  • Overloaded []
    • Access one character
    • No range checking (if subscript invalid)
  • at function
    • s1.at(10)
    • Character at subscript 10
    • Has bounds checking; will end program if invalid (learn more in Chapter 13)

The programs of Figs. 3.28-3.30 reimplements the program of Figs. 3.18-3.21, using standart class string.

Figure 3.28: Standart library class string (part 1 of 2).

Figure 3.29: Standart library class string (part 2 of 2).

Figure 3.30: Standart library class string, output.

• Class vector
  • Header $<$vector$>$, namespace std
  • Store any type; vector$<$ int $>$ myArray(10)
  • Function size ( myArray.size() )
  • Overloaded []; get specific element, myArray[3]
  • Overloaded !=, ==, and =; inequality, equality, assignment

The programs of Figs. 3.31-3.34 reimplements the program of Figs. 3.8-3.11, using standart class vector.

Figure 3.31: Standart library class vector. (part 1 of 3)

Figure 3.32: Standart library class vector. (part 2 of 3)

Figure 3.33: Standart library class vector. (part 3 of 3)

Figure 3.34: Standart library class vector, output.