Cheatography
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Standard Sytemtypes and their range
int8_t |
-128 to 127 |
uint8_t |
0 to 255 |
int16_t |
-32768 to 32767 |
uint16_t |
0 to 65535 |
int32_t |
-2147483648 to 2147483647 |
uint32_t |
0 to 4294967295 |
int64_t |
-9.2 * 1018 to 9.2 * 1018 |
uint64_t |
0 to 1.8 * 1019 |
Literals & Co.
255 |
Integer |
0xaf |
Hexadecimal Integer |
1234.0 |
double |
234.243f |
float |
true |
bool |
"Hello World" |
string/c-string |
'a' |
char |
Preprocessor
#include <LIB> |
Includes standard header file LIB |
#include "Header.h" |
Includes Header.h file |
#define PI 3.14159265359 |
Defines Easy Macro |
#define f(a,b) a+b |
More Complex Macro |
#undef PI |
Remove Definition |
#ifdef PI |
Checks for definition, if true, code will be compiled |
#else |
Else part of the above if-statement |
#endif |
Ends the if-statement |
Nullpointer
int* pInt;
//old, deprecated:
if(pInt == NULL)
//new:
if(pInt == nullptr)
//still valid:
if(!pInt) |
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|
Bitwise Operators
& |
Bitwise AND |
| |
Bitwise OR |
^ |
Bitwise XOR |
~ |
Bitwise NOT |
<< |
Shift left |
>> |
Shift right |
Boolean Logic
== |
Test of equality |
!= |
Test of non-equality |
< |
Less than |
> |
Greater than |
<= |
Less than or equal |
>= |
Greater than or equal |
! |
NOT |
&& |
AND |
|| |
OR |
Boolean expressions in C++ are evaluated left-to-right!
Basic Operators
+ |
addition |
- |
subtraction |
* |
multiplication |
/ |
division |
% |
modulo |
++var |
increase before evaluation |
var++ |
increase after evaluation |
condition ? result : alternative; |
short form of if-like structure |
:: |
Scope Operator |
-> |
pointer-to-member |
. |
Access member |
<< >> |
Bitshift(with streams: input/output) |
Pointers: Quick and dirty
& |
Gets RAM adress of Variable(to save into pointer) |
* |
Dereferences pointer(returns it´s content) or defines a variable to be a pointer |
-> |
Access pointer class member. same as (*pointer).member() |
new |
Create new object on heap, returns pointer to object |
delete |
Remove object at the pointer on heap |
Pointers allocate space on heap, normal variables on stack!
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|
using replaces typedef
//typedef is deprecated
typedef uint32_t uint32;
//now: using directive!
//using identifier = type_name;
using uint32 = uint32_t; |
Auto Datatype
//auto is an automatic datatype:
int x = 4; //equals:
auto y = 4;
//works for most cases, esp. STL:
for(std::vector<int>::Iterator it = v.begin().....)
//with auto:
for(auto it = v.begin; it != v.end(); ++it) |
Compile-time assertion check
static assert(bool_constexpr, string) |
Multithreading
//Thread Creation & Management:
void thread_func(int a)
{
std::cout << "My Number is: " << a;
}
main()
{
std::thread t1(thread_func(1));
t1.join();
}
//Synchronization via:
std::mutex.lock();
std::mutex.unlock(); |
Range based loops
//Easy range based loop:
std::vector<int> vec = .....;
for(int i : vec) //foreach i in vec
//Same with auto:
const auto vi = ....;
for(auto i : vi) |
Works with all Containers with begin() and end()
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Comments
Very basic and straightforward. Would have preferred to have the comments placed to the right instead of above and readjust other parts to the second page to accommodate proper spacing.
Thanks.
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