[Linux_C]

C與C++的敘述

C是作為一種中間語言，即介於進階商業應用程式語言如COBOL，以及直達機器、高性能但是不易於使用的組合語言。C是要實作結構化的程式設計，這種方法將問題分解為較小且可重覆的單元，叫作程序。

C++是作為一個物件導向程式設計方法和C之間的橋梁而創立的，是世界上最流行的商業軟體發展設計語言。其目標就是為了將物件導向的設計方法提供給快速、商業化的軟體發展作為一種平台。

How about JAVA ?

How about Android ?

How about UML ?

[Linux_C]004

來源為wiki的Operators in C and C++

方便未來 重載運算子 用
關於C++ operator介紹如下：

Arithmetic operators
Operator name		Syntax	Can overload	Included in C	Prototype examples
					As member of K
Basic assignment		a = b	Yes	Yes	R& K::operator =(S b);
Addition		a + b	Yes	Yes	R K::operator +(S b);
Subtraction		a - b	Yes	Yes	R K::operator -(S b);
Unary plus (integer promotion)		+a	Yes	Yes	R K::operator +();
Unary minus (additive inverse)		-a	Yes	Yes	R K::operator -();
Multiplication		a * b	Yes	Yes	R K::operator *(S b);
Division		a / b	Yes	Yes	R K::operator /(S b);
Modulo (integer remainder)		a % b	Yes	Yes	R K::operator %(S b);
Increment	Prefix	++a	Yes	Yes	R& K::operator ++();
	Postfix	a++	Yes	Yes	R K::operator ++(int);
					Note: C++ uses the unnamed dummy-parameter int to differentiate between prefix and suffix increment operators.
Decrement	Prefix	--a	Yes	Yes	R& K::operator --();
	Postfix	a--	Yes	Yes	R K::operator --(int);
					"Note: C++ uses the unnamed dummy-parameter int to differentiate between prefix and suffix decrement operators."
Comparison operators/relational operators
Operator name		Syntax	Can overload	Included in C	Prototype examples
					As member of K
Equal to		a == b	Yes	Yes	bool K::operator ==(S const& b);
Not equal to		a != b a not_eq b	Yes	Yes	bool K::operator !=(S const& b);
Greater than		a > b	Yes	Yes	bool K::operator >(S const& b);
Less than		a < b	Yes	Yes	bool K::operator <(S const& b);
Greater than or equal to		a >= b	Yes	Yes	bool K::operator >=(S const& b);
Less than or equal to		a <= b	Yes	Yes	bool K::operator <=(S const& b);
Logical operators
Operator name		Syntax	Can overload	Included in C	Prototype examples
					As member of K
Logical negation (NOT)		!a not a	Yes	Yes	R K::operator !();
Logical AND		a && b a and b	Yes	Yes	R K::operator &&(S b);
Logical OR		a || b a or b	Yes	Yes	R K::operator ||(S b);
Bitwise operators
Operator name		Syntax	Can overload	Included in C	Prototype examples
					As member of K
Bitwise NOT		~a compl a	Yes	Yes	R K::operator ~();
Bitwise AND		a & b a bitand b	Yes	Yes	R K::operator &(S b);
Bitwise OR		a | b a bitor b	Yes	Yes	R K::operator |(S b);
Bitwise XOR		a ^ b a xor b	Yes	Yes	R K::operator ^(S b);
Bitwise left shift		a << b	Yes	Yes	R K::operator <<(S b);
Bitwise right shift		a >> b	Yes	Yes	R K::operator >>(S b);
Member and pointer operators
Operator name		Syntax	Can overload	Included in C	Prototype examples
					As member of K
Array subscript		a[b]	Yes	Yes	R& K::operator [](S b);
Indirection ("object pointed to by a")		*a	Yes	Yes	R& K::operator *();
Address ("address of a")		&a	Yes	Yes	R K::operator &();
Structure dereference ("member b of object pointed to bya")		a->b	Yes	Yes	R* K::operator ->();
Structure reference ("member b of object a")		a.b	No	Yes	N/A
Object pointed to by member b of object pointed to by a		a->*b	Yes	No	R& K::operator ->*(S b);
Object pointed to by member b of object a		a.*b	No	No	N/A
Other operators
Operator name		Syntax	Can overload	Included in C	Prototype examples
					As member of K
Function call See Function object.		a(a1, a2)	Yes	Yes	R K::operator ()(S a, T b, ...);
Comma		a, b	Yes	Yes	R K::operator ,(S b);
Ternary conditional		a ? b : c	No	Yes	N/A
Scope resolution		a::b	No	No	N/A
User-defined literals since C++11		"a"_b	Yes	No	N/A
Conversion ( C-style cast)		(type) a type(a)	Yes	Yes	K::operator R();
					Note: for user-defined conversions, the return type implicitly and necessarily matches the operator name.
Size-of		sizeof (a) sizeof (type)	No	Yes	N/A
Size of parameter pack since C++11		sizeof...(Args)	No	No	N/A
Align-of since C++11		alignof (type) or _Alignof (type)	No	Yes	N/A
Allocate storage		new type	Yes	No	void* K::operator new(size_t x);
Allocate storage (array)		new type[n]	Yes	No	void* K::operator new[](size_t a);
Deallocate storage (delete returns void so it isn't strictly speaking an operator)		delete a	Yes	No	void K::operator delete(void *a);
Deallocate storage (array)		delete[] a	Yes	No	void K::operator delete[](void *a);
Type identification		typeid (a) typeid (type)	No	No	N/A
static_cast conversion		static_cast<type>(a)	No	No	N/A
dynamic_cast conversion		dynamic_cast<type>(a)	No	No	N/A
const_cast conversion		const_cast<type>(a)	No	No	N/A
reinterpret_cast conversion		reinterpret_cast<type>(a)	No	No	N/A
Exception check since C++11		noexcept(a)	No	No	N/A

[Linux_C]003

常見指令

常見數學函數
ceil(f)	將 f 變為最大整數
floor(f)	將 f 變為最小整數
sqrt(f)	f的平方根
exp(f)	自然指數
log(f)	e為基底的自然對數
log10(f)	10為基底的自然對數
pow(f,g)	f的g次方
sin(f)	sin
cos(f)	cos
tan(f)	tan
fabs(f)	浮點數取絕對值
fmod(f,g)	計算f/g的餘數
acos,asin,atan	其餘相關三角函數
acosh,asinh,atanh
cosh,sinh,tanh
常見字串與字元函數
strcpy(s1,s2)	s2複製到s1，直到遇到null符號
strncpy(s1,s2,n)	s2中n個字元複製到s1，直到遇到null符號
strcat(s1,s2)	s2複製到s1的結尾
strncat(s1,s2,n)	s2中的n個字元複製到s1的結尾
strcmp(s1,s2)	s2與s1進行比較
strncmp(s1,s2,n)	s2中n個字元與s1進行比較
strlen(s1)	字串長度
strlwr(s1)	轉為小寫
strupr(s1)	轉為大寫
strtok(s1,s2)	以s2分割s1中的內容
strtod(s1),strtol(s1)	轉為整數或長整數
一般常見函數
system(s1)	s1作為命令對系統下指令
malloc(n)	分配n bytes記憶體
free(ptr)	釋放malloc或realloc
realloc(ptr,n)	替malloc在增加n bytes
abs(n)	絕對值
asctime(t)	時間
bsearch()	排序的資料進行二分法搜尋
qsort()	進行排序
isalpha(c)	是否為字母
isdigit(c)	是否為數字
islower(c)	是否為小寫
isupper(c)	是否為大寫