1CISC181 Introduction to Computer ScienceDr McCoy1Dr. McCoyLecture 6September 17, 2009Another Look at Switch• Exercise 2.63 – “The Twelve Days of Christmas” Song.Thi l l h th f2•This program clearly shows the use of break in the switch statement.Chapter 3 - Functions• So far our programs have been pretty simple made up of control structures and “pre-packaged” functions available in the C Standard library3C Standard library.• Programmer can also write functions to define specific tasks that might be done several times in a program.Function• Functions need only be defined once.• The functions can be called many times in a program.Thi hid th d t il f h t i4•This hides the details of what is happening.• Example: perfect place is to print out money value given integer representation.Invoking 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 function5provides any arguments the function needs.• Generally, functions return a value – the thing computed in the function call.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.273.3 Math Library Functions• Perform common mathematical calculations– Include the header file <cmath>• Functions called by writing– functionName (argument);or 2003 Prentice Hall, Inc. All rights reserved.– functionName(argument1, argument2, …);•Examplecout << sqrt( 900.0 );– sqrt (square root) function The preceding statement would print 30– All functions in math library return a double83.3 Math Library Functions• Function arguments can be– Constants• sqrt( 4 );– Variables• sqrt( x );Ei 2003 Prentice Hall, Inc. All rights reserved.–Expressions• sqrt( sqrt( x ) ) ;• sqrt( 3 - 6x );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-it bfmod( 13.657, 2.333 ) is 1.992 2003 Prentice Hall, Inc. All rights reserved.point number 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 M ath lib rary func tions. 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-it bfmod( 13.657, 2.333 ) is 1.992 2003 Prentice Hall, Inc. All rights reserved.point numberlog( 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 M ath lib rary func tions. 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-it bfmod( 13.657, 2.333 ) is 1.992 2003 Prentice Hall, Inc. All rights reserved.point number 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 M ath lib rary func tions. 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-it bfmod( 13.657, 2.333 ) is 1.992 2003 Prentice Hall, Inc. All rights reserved.point numberlog( 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( …
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