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Math Library Functions
name of the function
what it does
data type of argument
data type of returned value
Math Library Functions
Syntax: function_name (argument);function_name (argument);
Ex. sqrt(49) pow(2.1, 3)
abs(-34.5) cos(30)
abs(34.5)
*
Math Library Functions
nested functions
sqrt( pow ( fabs (-4), 3) ) =
sqrt( pow ( 4.0 , 3) ) =
sqrt( 64.0 ) = 8.0
* * *
Type Casting
The explicit conversion of a value from one data type to another.
Syntax: data_type (expression)data_type (expression)
* *
int (5.34 * 1.68)
int (8.9712)This returns a value of 8.
Type Casting
someInt = someDouble - 8.2;
someInt = int(someDouble - 8.2);
These are identical statements.These are identical statements.
* *
Type Coercion
The implicit (automatic) conversion of a value from one data type to another.
someDouble = 42; is stored as 42.0
someInt = 11.9; is stored as 11
*
Math Function Example
#include <math.h> // needed for the exp functionint year;int year;long int population;long int population;
year = 1995;year = 1995;
population = 5.5 * population = 5.5 * exp(exp(0.02*(year-1990)0.02*(year-1990)));;cout << "The estimated population for " << yearcout << "The estimated population for " << year
<< " is "<<population << "."; << " is "<<population << ".";
year = 2012;year = 2012;cout << "The estimated population for " << yearcout << "The estimated population for " << year
<< " is "<< population <<"."; << " is "<< population <<".";
Math Function Example
Output:
The estimated population for 1995 is 6.
The estimated population for 2012 is 8.
cin
cin >> my_num;
The keyboard entry is stored into a local
variable called my_num.
Read as: “get from my_num”.
cin(concatenation)
Syntax: cin >> var1 >> var2 >> ...cin >> var1 >> var2 >> ...
cin >> first >> last >> my_num;
*
cin >> qz1 >> qz2 >> qz3 >> qz4;
cin Example 1
int num1, num2, num3;double average;
cout << "Enter three integer numbers: ";cin >> num1 >> num2 >> num3;average = (num1 + num2 + num3) / 3.0;cout << "The average is " << average;cout << '\n';
cin Example 2
double radius, circumference;
double pi = 3.1416;
cout << "Enter the radius of a circle: ";
cin >> radius;
circumference = 2 * pi * radius;
cout << "The circumference of a circle of radius "
<< radius << " is " << circumference <<‘\n’;
cin Example 2
Output:
Enter the radius of a circle: 14
The circum ... circle of radius 14 is 87.9648
cin Example 3
double celsius, faren;
cout <<"Enter the temperature in degrees Fahrenheit: ";cin >> faren;
celsius = 5.0/9.0 * (faren - 32.0);
cout << faren <<" degrees Fahrenheit equals "<< celsius << " degrees celsius.\n";
cin Example 3
Output:
Enter the temperature in degrees Farenheit: 8282 degrees Farenheit equals 27.7777 degrees celsius.
const Qualifier
Syntax: const DataType Name = Literal Value;const DataType Name = Literal Value;
Examples
const double PI = 3.1416;
const double OT_RATE = 1.5;
*
const Qualifier
double radius, area;
const double PI = 3.1416
cout << “Enter the radius: “;
cin >> radius;
cout << “The area is your circle is “
<< PI * radius * radius;
*
Common Programming Errors
not initializing variables before useforgetting >>>> to separate variables in cin
applying ++++ or ---- to an expression
(x-y)++
Why isn’t phonetic spelled as it sounds?
Why do they put Braille dots on the keypad of a drive-up ATM?
How many Microsoft technicians does it How many Microsoft technicians does it take to change a light bulb?take to change a light bulb? Three: two holding the ladder and one
to screw the bulb into a faucet.
“Lack of brains hinders research” The Columbus Dispatch, 16 April 1996
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