1. CSE 100
<math.h>
Input: cin
type casting

2. Math Library Functions
math.h
sqrt(n) fabs(n) cos(n)
log10(n) log(n)
pow(b, n) etc.
* * *

3. Math Library Functions
name of the function
what it does
data type of argument
data type of returned value

4. Math Library Functions
Ex. sqrt(49) pow(2.1, 3)
abs(-34.5) cos(30)
abs(34.5)
Syntax: function_name (argument); *

5. Math Library Functions
sqrt( pow ( fabs (-4), 3) ) =
sqrt( pow ( , 3) ) =
sqrt( 64.0 ) = 8.0
nested functions
* * *

6. Type Casting
The explicit conversion of a value from one data type to another.
Syntax: data_type (expression)
int (5.34 * 1.68)
int (8.9712) This returns a value of 8.
* *

7. Type Casting someInt = someDouble - 8.2;
someInt = int(someDouble - 8.2);
These are identical statements.
* *

8. Type Coercion
The implicit (automatic) conversion of a value from one data type to another.
someDouble = 42; is stored as someInt = 11.9; is stored as 11 *

9. Math Function Example
#include <math.h> // needed for the exp function
int year;
long int population;
year = 1995;
population = 5.5 * exp(0.02*(year-1990));
cout << "The estimated population for " << year << " is "<<population << ".";
year = 2012;
cout << "The estimated population for " << year << " is "<< population <<".";

10. Math Function Example
5.5 e .02(year-1900)
5.5 * exp(0.02*(year-1990))

11. Math Function Example Output: The estimated population for 1995 is 6.

12. cin cin >> my_num; The keyboard entry is stored into a local
variable called my_num.
Read as: “get from my_num”.

13. cin Syntax: cin >> var1;
Examples: cin >> last_name; cin >> ch; cin >> my_id#; *

14. Syntax: cin >> var1 >> var2 >> ...
cin (concatenation)
Syntax: cin >> var1 >> var2 >> ...
cin >> first >> last >> my_num;
cin >> qz1 >> qz2 >> qz3 >> qz4; *

15. cin & cout main() { cout << cin >> }
standard device standard device (keyboard) (screen)

16. cin & cout cout cin << >> insertion extraction
<< >>
insertion extraction
“put to” “get from”
whitespace characters ignored

17. 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';

18. cin Example 1
Output:
The average is

19. 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’;

20. cin Example 2 Output: Enter the radius of a circle: 14
The circum ... circle of radius 14 is

21. cin Example 3 double celsius, faren;
cout <<"Enter the temperature in degrees Fahrenheit: ";
cin >> faren;
celsius = 5.0/9.0 * (faren );
cout << faren <<" degrees Fahrenheit equals "<< celsius
<< " degrees celsius.\n";

22. cin Example 3 Output: Enter the temperature in degrees Farenheit: 82
82 degrees Farenheit equals degrees celsius.

23. const Qualifier Syntax: const DataType Name = Literal Value;
Examples const double PI = ; const double OT_RATE = 1.5; *

24. const Qualifier
double radius, area; const double PI = cout << “Enter the radius: “; cin >> radius;
cout << “The area is your circle is “
<< PI * radius * radius; *

25. Common Programming Errors
not initializing variables before use
forgetting >> to separate variables in cin
applying ++ or -- to an expression
(x-y)++

26. 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 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