variables and types in objective-c and c programming
DESCRIPTION
Course Link: http://skl.sh/11kA0im Website: http://iPhoneDev.tv Learn how variables and types work in Objective-C and C programming languages.TRANSCRIPT
Paul Solt iPhoneDev.tv
Variables and TypesThe buildings blocks of apps
Paul Solt iPhoneDev.tv
Coffee
=+
Paul Solt iPhoneDev.tv
Coffee
•17 ml water : 1 g coffee
•950 ml water / 17 ml/g = ?
•55.8 g coffee
Paul Solt iPhoneDev.tv
VariablesGive the CPU something to remember
Paul Solt iPhoneDev.tv
// Declare a variable to store waterfloat water;
// Store the amount of water to usewater = 950; // milliliters
// Display messageprintf("Brew %f milliliters of coffee", water);
Paul Solt iPhoneDev.tv
int age = 26;
Paul Solt iPhoneDev.tv
int age = 26;type
Paul Solt iPhoneDev.tv
int age = 26;type name
Paul Solt iPhoneDev.tv
int age = 26;type name expression
Paul Solt iPhoneDev.tv
int age = 26;type name expression
assignmentoperator
Paul Solt iPhoneDev.tv
int age = 26;
Paul Solt iPhoneDev.tv
int age = 26;
26age
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
a
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
a
b
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b; b
5a
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
5a
20b
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
5a
205+b
b
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
5a
205+20
b
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
5a
255+20
b
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
5a
25b
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
5a-b
a
25b
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
55-25
a
25b
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
-205-25
a
25b
Paul Solt iPhoneDev.tv
int a;int b;a = 5;b = 20;b = 5 + b;a = a - b;
-20a
25b
Paul Solt iPhoneDev.tv
TypesWhat kind of information are we storing?
Paul Solt iPhoneDev.tv
•short/int/long: -1,0,1•float/double: 3.14•char: ‘a’, ‘b’, ‘c’•pointers: int * (memory address)•struct: composition (x, y)
Paul Solt iPhoneDev.tv
short small = 12;int medium = 2000000;long large = 90133726844735000;
Paul Solt iPhoneDev.tv
float smaller = 3.14;double larger = 3.14159265359;
Paul Solt iPhoneDev.tv
char firstLetter = 'a';char percent = '%';
Paul Solt iPhoneDev.tv
int *address = 0;int x = 18;address = &x;*address = 27;
address x
0x1234 0x5544
Paul Solt iPhoneDev.tv
int *address = 0;int x = 18;address = &x;*address = 27;
address x
0x1234 0x5544
0
Paul Solt iPhoneDev.tv
int *address = 0;int x = 18;address = &x;*address = 27;
address x
0x1234 0x5544
0 18
Paul Solt iPhoneDev.tv
int *address = 0;int x = 18;address = &x;*address = 27;
address x
0x1234 0x5544
0 18
Paul Solt iPhoneDev.tv
int *address = 0;int x = 18;address = &x;*address = 27;
address x
0x1234 0x5544&x
0 18
Paul Solt iPhoneDev.tv
int *address = 0;int x = 18;address = &x;*address = 27;
address x
0x1234 0x5544
0x5544
&x
18
Paul Solt iPhoneDev.tv
int *address = 0;int x = 18;address = &x;*address = 27;
address x
0x1234 0x5544
0x5544
&x
18
Paul Solt iPhoneDev.tv
int *address = 0;int x = 18;address = &x;*address = 27;
address x
0x1234 0x5544
0x5544 18*address
Paul Solt iPhoneDev.tv
int *address = 0;int x = 18;address = &x;*address = 27;
address x
0x1234 0x5544
0x5544 27*address
Paul Solt iPhoneDev.tv
int *address = 0;int x = 18;address = &x;*address = 27;
address x
0x1234 0x5544
0x5544 27
Paul Solt iPhoneDev.tv
struct Point { int x; int y;};
...
struct Point a;a.x = 25;a.y = 100;
Paul Solt iPhoneDev.tv
struct Point { int x; int y;};
...
struct Point a;a.x = 25;a.y = 100;
(25, 100)y
x
Paul Solt iPhoneDev.tv
•short/int/long: -1,0,1•float/double: 3.14•char: ‘a’, ‘b’, ‘c’•pointers: int * (memory address)•struct: composition (x, y)
Paul Solt iPhoneDev.tv