CISC181 Introduction to Computer Science Dr. McCoy Lecture 6 September 17, 2009Another Look at SwitchChapter 3 - FunctionsFunctionInvoking Functions3.2 Program Components in C++3.3 Math Library FunctionsSlide 8Slide 9Slide 10Slide 11Slide 12Slide 13Math Functions3.4 Functions3.5 Function DefinitionsSlide 17Slide 18fig03_03.cpp (1 of 2)fig03_03.cpp (2 of 2) fig03_03.cpp output (1 of 1)fig03_04.cpp (1 of 2)fig03_04.cpp (2 of 2) fig03_04.cpp output (1 of 1)Exercise 3.213.6 Function PrototypesSlide 25Slide 263.7 Header Files1CISC181 Introduction to Computer ScienceDr. McCoyLecture 6September 17, 20092Another Look at Switch•Exercise 2.63 – “The Twelve Days of Christmas” Song.•This program clearly shows the use of break in the switch statement.3Chapter 3 - Functions•So far our programs have been pretty simple made up of control structures and “pre-packaged” functions available in the C Standard library.•Programmer can also write functions to define specific tasks that might be done several times in a program.4Function•Functions need only be defined once.•The functions can be called many times in a program.•This hides the details of what is happening.•Example: perfect place is to print out money value given integer representation.5Invoking Functions•A function is invoked (i.e., made to perform its designated task) by a function call which specifies the function name and provides any arguments the function needs.•Generally, functions return a value – the thing computed in the function call. 2003 Prentice Hall, Inc. All rights reserved.63.2 Program Components in C++•Boss to worker analogy–A boss (the calling function or caller) asks a worker (the called function) to perform a task and return (i.e., report back) the results when the task is done. 2003 Prentice Hall, Inc. All rights reserved.73.3 Math Library Functions•Perform common mathematical calculations–Include the header file <cmath>•Functions called by writing–functionName (argument);or–functionName(argument1, argument2, …);•Examplecout << sqrt( 900.0 );–sqrt (square root) function The preceding statement would print 30–All functions in math library return a double 2003 Prentice Hall, Inc. All rights reserved.83.3 Math Library Functions•Function arguments can be–Constants•sqrt( 4 );–Variables•sqrt( x );–Expressions•sqrt( sqrt( x ) ) ;•sqrt( 3 - 6x ); 2003 Prentice Hall, Inc. All rights reserved.9Method Description Example ceil( x ) rounds x to the smallest integer not less than x ceil( 9.2 ) is 10.0 ceil( -9.8 ) is -9.0 cos( x ) trigonometric cosine of x (x in radians) cos( 0.0 ) is 1.0 exp( x ) exponential function ex exp( 1.0 ) is 2.71828 exp( 2.0 ) is 7.38906 fabs( x ) absolute value of x fabs( 5.1 ) is 5.1 fabs( 0.0 ) is 0.0 fabs( -8.76 ) is 8.76 floor( x ) rounds x to the largest integer not greater than x floor( 9.2 ) is 9.0 floor( -9.8 ) is -10.0 fmod( x, y ) remainder of x/y as a floating-point number fmod( 13.657, 2.333 ) is 1.992 log( x ) natural logarithm of x (base e) log( 2.718282 ) is 1.0 log( 7.389056 ) is 2.0 log10( x ) logarithm of x (base 10) log10( 10.0 ) is 1.0 log10( 100.0 ) is 2.0 pow( x, y ) x raised to power y (xy) pow( 2, 7 ) is 128 pow( 9, .5 ) is 3 sin( x ) trigonometric sine of x (x in radians) sin( 0.0 ) is 0 sqrt( x ) square root of x sqrt( 900.0 ) is 30.0 sqrt( 9.0 ) is 3.0 tan( x ) trigonometric tangent of x (x in radians) tan( 0.0 ) is 0 Fig. 3.2 Math library functions. 2003 Prentice Hall, Inc. All rights reserved.10Method Description Example ceil( x ) rounds x to the smallest integer not less than x ceil( 9.2 ) is 10.0 ceil( -9.8 ) is -9.0 cos( x ) trigonometric cosine of x (x in radians) cos( 0.0 ) is 1.0 exp( x ) exponential function ex exp( 1.0 ) is 2.71828 exp( 2.0 ) is 7.38906 fabs( x ) absolute value of x fabs( 5.1 ) is 5.1 fabs( 0.0 ) is 0.0 fabs( -8.76 ) is 8.76 floor( x ) rounds x to the largest integer not greater than x floor( 9.2 ) is 9.0 floor( -9.8 ) is -10.0 fmod( x, y ) remainder of x/y as a floating-point number fmod( 13.657, 2.333 ) is 1.992 log( x ) natural logarithm of x (base e) log( 2.718282 ) is 1.0 log( 7.389056 ) is 2.0 log10( x ) logarithm of x (base 10) log10( 10.0 ) is 1.0 log10( 100.0 ) is 2.0 pow( x, y ) x raised to power y (xy) pow( 2, 7 ) is 128 pow( 9, .5 ) is 3 sin( x ) trigonometric sine of x (x in radians) sin( 0.0 ) is 0 sqrt( x ) square root of x sqrt( 900.0 ) is 30.0 sqrt( 9.0 ) is 3.0 tan( x ) trigonometric tangent of x (x in radians) tan( 0.0 ) is 0 Fig. 3.2 Math library functions. 2003 Prentice Hall, Inc. All rights reserved.11Method Description Example ceil( x ) rounds x to the smallest integer not less than x ceil( 9.2 ) is 10.0 ceil( -9.8 ) is -9.0 cos( x ) trigonometric cosine of x (x in radians) cos( 0.0 ) is 1.0 exp( x ) exponential function ex exp( 1.0 ) is 2.71828 exp( 2.0 ) is 7.38906 fabs( x ) absolute value of x fabs( 5.1 ) is 5.1 fabs( 0.0 ) is 0.0 fabs( -8.76 ) is 8.76 floor( x ) rounds x to the largest integer not greater than x floor( 9.2 ) is 9.0 floor( -9.8 ) is -10.0 fmod( x, y ) remainder of x/y as a floating-point number fmod( 13.657, 2.333 ) is 1.992 log( x ) natural logarithm of x (base e) log( 2.718282 ) is 1.0 log( 7.389056 ) is 2.0 log10( x ) logarithm of x (base 10) log10( 10.0 ) is 1.0 log10( 100.0 ) is 2.0 pow( x, y ) x raised to power y (xy) pow( 2, 7 ) is 128 pow( 9, .5 ) is 3 sin( x ) trigonometric sine of x (x in radians) sin( 0.0 ) is 0 sqrt( x ) square root of x sqrt( 900.0 ) is 30.0 sqrt( 9.0 ) is 3.0 tan( x ) trigonometric tangent of x (x in radians) tan( 0.0 ) is 0 Fig. 3.2 Math library functions. 2003 Prentice Hall, Inc. All rights reserved.12Method Description Example ceil( x ) rounds x to the smallest integer not less than x ceil( 9.2 ) is 10.0 ceil( -9.8 ) is -9.0 cos( x ) trigonometric cosine of x (x in radians) cos( 0.0 ) is 1.0 exp( x ) exponential function ex exp( 1.0 ) is 2.71828 exp( 2.0 ) is 7.38906 fabs( x ) absolute value of x fabs( 5.1 ) is 5.1 fabs( 0.0 ) is 0.0 fabs( -8.76 ) is 8.76 floor( x ) rounds x to the largest integer not greater than x floor( 9.2 ) is 9.0 floor( -9.8 ) is -10.0 fmod( x, y ) remainder of x/y as a floating-point number fmod( 13.657, 2.333 ) is 1.992 log( x ) natural logarithm of x (base e) log( 2.718282 ) is 1.0 log( 7.389056 ) is 2.0 log10( x ) logarithm of x (base 10) log10( 10.0 ) is 1.0 log10( 100.0 ) is 2.0 pow( x, y ) x raised to power y (xy) …