Difference between revisions of "Week 5"
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In C, everything upcasts. (so if you have an expression, it will upcast all the variables to the largest type). | In C, everything upcasts. (so if you have an expression, it will upcast all the variables to the largest type). | ||
+ | |||
+ | '''<u>New Concepts</u>''' | ||
+ | |||
+ | Page 36 - review it carefully. | ||
+ | |||
+ | difference between a structure and a class in C++ structure is public by default, classes are private by default. | ||
+ | |||
+ | in c - instantiate a structure: struct student s; | ||
+ | c++ - student s; | ||
+ | |||
+ | union - places all the variables in the same place in memory. | ||
+ | enum weekdays(sun, mon, tue, wed, thu, fri, sat) - will create 7 constant ints starting from 0 | ||
+ | |||
+ | typedef int age - adds the name "age" as an integer to the C library. so now u can say "age a = 34;" - same as saying int a = 34 | ||
+ | |||
+ | c = 20 || 50 | ||
+ | |||
+ | c = true because both 20 and 50 are not 0 which is false. | ||
+ | |||
+ | in the ? : operator both values must be same data type. | ||
+ | ignore page 37 | ||
+ | |||
+ | bitwise operators?? | ||
+ | AC 1010 1100 = A | ||
+ | 4E 0100 1110 = B | ||
+ | |||
+ | A && B = 0000 0001 | ||
+ | A & B = 0000 1100 | ||
+ | A | B = 1110 1110 | ||
+ | ! A = 0000 0000 | ||
+ | ~A = 0101 0011 | ||
+ | A^B = 1110 0010 | ||
+ | |||
+ | A << 1 = 0101 1000 // left shift | ||
+ | B << 2 = 0011 1000 | ||
+ | |||
+ | right shift - signed && left bit 1 if both these conditions are true, then fill the left with 1's otherwise 0's | ||
+ | |||
+ | B >> 3 = 0000 1001 | ||
+ | A >> 2 = 1110 1011 |
Latest revision as of 14:14, 10 June 2010
Creating pointers to functions
type foo(type 1, type2, type3, etc);
type (*P)(type1, type2, type3, etc);
P is a pointer variable to a function foo.
Assigning a function to a pointer variable:
P = foo;
In C (or C++), x = (*P)(type1, type2, type3);
In C++, x = P(y, z, x);
In C, everything upcasts. (so if you have an expression, it will upcast all the variables to the largest type).
New Concepts
Page 36 - review it carefully.
difference between a structure and a class in C++ structure is public by default, classes are private by default.
in c - instantiate a structure: struct student s; c++ - student s;
union - places all the variables in the same place in memory. enum weekdays(sun, mon, tue, wed, thu, fri, sat) - will create 7 constant ints starting from 0
typedef int age - adds the name "age" as an integer to the C library. so now u can say "age a = 34;" - same as saying int a = 34
c = 20 || 50
c = true because both 20 and 50 are not 0 which is false.
in the ? : operator both values must be same data type. ignore page 37
bitwise operators?? AC 1010 1100 = A 4E 0100 1110 = B
A && B = 0000 0001 A & B = 0000 1100 A | B = 1110 1110 ! A = 0000 0000 ~A = 0101 0011 A^B = 1110 0010
A << 1 = 0101 1000 // left shift B << 2 = 0011 1000
right shift - signed && left bit 1 if both these conditions are true, then fill the left with 1's otherwise 0's
B >> 3 = 0000 1001 A >> 2 = 1110 1011