Object oriented programming 9 expressions and type casting in c++
- 1. Object Oriented Programming: 9 Expressions and Type Casting in C++ Prof Neeraj Bhargava Vaibhav Khanna Department of Computer Science School of Engineering and Systems Sciences Maharshi Dayanand Saraswati University Ajmer
- 2. 2 Expressions • If all operands are integers – Expression is called an integral expression • Yields an integral result • Example: 2 + 3 * 5 • If all operands are floating-point – Expression is called a floating-point expression • Yields a floating-point result • Example: 12.8 * 17.5 - 34.50
- 3. 3 Mixed Expressions • Mixed expression: – Has operands of different data types – Contains integers and floating-point • Examples of mixed expressions: 2 + 3.5 6 / 4 + 3.9 5.4 * 2 – 13.6 + 18 / 2
- 4. 4 Mixed Expressions (continued) • Evaluation rules: – If operator has same types of operands • Evaluated according to the type of the operands – If operator has both types of operands • Integer is changed to floating-point • Operator is evaluated • Result is floating-point – Entire expression is evaluated according to precedence rules
- 5. 5 Type Conversion (Casting) • Implicit type coercion: when value of one type is automatically changed to another type • Cast operator: provides explicit type conversion static_cast<dataTypeName>(expression)
- 7. 7 string Type • Programmer-defined type supplied in ANSI/ISO Standard C++ library • Sequence of zero or more characters • Enclosed in double quotation marks • Null: a string with no characters • Each character has relative position in string – Position of first character is 0 • Length of a string is number of characters in it – Example: length of "William Jacob" is 13
- 8. 8 Input • Data must be loaded into main memory before it can be manipulated • Storing data in memory is a two-step process: – Instruct computer to allocate memory – Include statements to put data into memory
- 9. 9 Allocating Memory with Constants and Variables • Named constant: memory location whose content can’t change during execution • The syntax to declare a named constant is: • In C++, const is a reserved word
- 10. 10 Allocating Memory with Constants and Variables (continued) • Variable: memory location whose content may change during execution • The syntax to declare a named constant is:
- 11. 11 Putting Data into Variables • Ways to place data into a variable: – Use C++’s assignment statement – Use input (read) statements
- 12. Assignment • Explain the concept of typecasting in C++