Last Time…. Operators Arithmetic Operators Assignment Operators Increment/Decrement Operators Relational Operators Logical Operators Expression Statements Introduction to Library Functions

Precedence of Operators Evaluation the following Expressions: a) * 6 / 3 – 5 b) /

Summary of Operators

Defining constants  const Qualifier  #define directive

Automatic Type Conversion and Casts int count = 100; float avgWeight = 70F; double totalWeight = count * avgWeight; cout<<“The total weight in this room = ”<<totalWeight; Automatic Type Conversion, Compiler handles the type conversion

Static Casts int result; float a = 4.0; result = a * 3.56; > How do you cast to another type? >>Up-Cast >>Down-Cast

Implicit Type Conversion When an operator’s operands are of different data types, C++ will automatically convert them to the same data type. When a value is converted to a higher data type, it is said to be prompted. To demote a value means to convert it to a lower data type.

Two Rules Rule 1: When an operator works with two values of different values of different data types, the lower-ranking value is prompted to the type of the higher-ranking value. Rule 2: When the final value of and expression is assigned to a variable, it will be converted to the data type of that variable.

Explicit Type Conversion [A type cast expression lets you manually promote or demote a value in the same way that automatic conversion takes place.]

Syntax static_cast (Value) A variable or Literal value Data Type you wish to convert it to

int main() { int books, months; double booksPerMonth; cout<<“How many books do you plan to read?” cin>>books; cout<<“How many month will it take you to read them?” cin>>months; booksPerMonth = books/months; cout<<“That is”<<booksPerMonth<<“books per month.\n”; system(“pause”); return 0; } How would you prevent the INTEGER DIVISION?

Quiz _1 : Implement an Pseudocode Write a program that implements the following algorithm. Start Read the total hours the employee has worked, TotalHours Read the hourly rate of pay for the employee, HourlyRate GrossSalary = TotalHours * HourlyRate Tax = GrossSalary * 0.1 NetSalary = GrossSalary - Tax Display NetSalary Stop

Quiz _2:Currency [Write a program that will convert U.S. dollar amounts to Japanese yen and to euros. The conversion factors to use are 1dollar = yen and 1 dollar = euros]

[Solutions to the Quiz Questions]

Library Functions Yared Semu Addis Ababa Institute of Technology April 2012

Library Functions In C++, we make extensive use of library functions to accomplish tasks. –Mathematical Functions –IO Manipulators

Mathematical Functions The mathematical functions allow us to do mathematical operations. These operations include: raising a number to a certain power, computing the square root of a number, computing the cosine of an angle, etc.... These functions are defined in the header file math.h (or cmath in standard C++). #include

Mathematical Functions … sqrt is the name of the function that performs the square root operation. This function takes one argument of type double and returns a result of type double.

Multiple Arguments When a function takes multiple arguments, they are separated by commas inside the parenthesis. This statement computes 3 raised to 4.

Mathematical Functions … The function that computes the power of two numbers is : More examples of mathematical functions are:

IO Manipulators IO Manipulators are operators used with the insertion operator (<<) to modify or manipulate the way data is displayed.  Other IO manipulators, which take arguments, are defined in the iomanip.h (or iomanip in standard C++) header file. #include

Commonly Used Manipulators General Output ManipulatorRangeDescription endlnowWrite a newline ('\n') and flush buffer. setw(n)next Sets minimum field width on output. (Note: A field is an area on a computer screen, where information such as characters or numbers can be entered and manipulated) Use left and right to justify the data appropriately in the field. Output is right justified by default. e.g. cout<<setw(7)<<n<<endl width(n)nextSame as setw(n)

IO Manipulators General Output ManipulatorRangeDescription leftnow Left justifies output in field width. Only useful after setw(n). rightnext Right justifies output in field width. Since this is the default, it is only used to override the effects of left. Only useful after setw(n). setfill(ch)all Only useful after setw. If a value does not entirely fill a field, the character ch will be used to fill in the other characters. Default value is blank. E.g. cout << setw(4) << setfill('0') << n << endl;

IO Manipulators Floating point output ManipulatorRangeDescription setprecision(n)all Sets the number of digits printed to the right of the decimal point. This applies to all subsequent floating point numbers written to that output stream. However, this won't make floating-point "integers" print with a decimal point. It's necessary to use fixed for that effect fixedall Used fixed point notation for floating-point numbers. Opposite of scientific. If no precision has already been specified, it will set the precision to 6 scientificall Formats floating-point numbers in scientific notation. Opposite of fixed.

IO Manipulators(Example) What is the output of this program?

Example- IO Manipulators Write a program that displays the output show below.

Exercises