CS106 Lab 2 - Variables declaration
- 1. Lab 2 CS106 - Fundamentals of Computer Science Presented by TA. Nada Kamel
- 2. Agenda Data types Variables declaration Character escapes Strings Literals Constants Presented by TA. Nada Kamel
- 3. Data Types Presented by TA. Nada Kamel
- 4. Data Types Data Type C++ Keyword Byte(s) Typical range Integer int 4 -2,147,483,648 to 2,147,483,647 Unsigned integer unsigned int 4 0 to 4,294,967,295 Long integer long 8 ~ -9 Billion to ~ 9 Billion Floating point float 4 +/- 3.4e +/- 38 (~7 digits) Double floating point double 8 +/- 1.7e +/- 308 (~15 digits) Character char 1 128 to 127 or 0 to 255 String/Text string ∞ - Presented by TA. Nada Kamel
- 5. Data Types (Cont.) Boolean bool Void void Presented by TA. Nada Kamel
- 6. Variable Declaration Presented by TA. Nada Kamel
- 7. Variable Declaration C++ requires every variable to be declared with its type BEFORE its first use. Examples: int height; char letter; float radius, diameter; In these examples, variables have an undetermined value. Presented by TA. Nada Kamel
- 8. Variable Initialization Allows variable to have a specific value from the moment it is declared. Example: int depth = 67; (data type) (identifier) = initial_value; Presented by TA. Nada Kamel
- 9. Character Escapes Presented by TA. Nada Kamel
- 10. Character Escapes Keyword Meaning n or endl newline r carriage return t tab v vertical tab b backspace a alert (beep sound) ’ single quote ” double quote ? question mark backslash Presented by TA. Nada Kamel
- 11. Strings Presented by TA. Nada Kamel
- 12. Strings Strings are able to store sequences of characters. To utilize strings we must include a directive #include <string> Can be initialized with any of the three valid initialization formats: string mystring = “Hello World!”; string mystring(“Hello World!”); string mystring {“Hello World!”}; Presented by TA. Nada Kamel
- 13. Strings (Cont.) To input a string you will need to use: getline(cin, mystring); If the user will enter one word only, cin >> mystring can be used. Example: #include <iostream> #include <string> void main() { string mystring; getline(cin, mystring); std:: cout << “The string entered is ” << mystring << endl; } Presented by TA. Nada Kamel
- 14. Literals Presented by TA. Nada Kamel
- 15. Literals Used to express particular values. Literal constants can be classified into: integers, floating-point, character, string, boolean. Examples: 707 -20589 3.14 1.6e-19 ‘z’ “Hello World!” true Presented by TA. Nada Kamel
- 16. Typed Constants Presented by TA. Nada Kamel
- 17. Constants Can be used to give names to constant values. Example: const float pi = 3.14159; The value of the constant variable cannot be changed after being initialized. Presented by TA. Nada Kamel
- 18. Any Questions? Presented by TA. Nada Kamel