The IOS development object-c operator

Blog Address : http://blog.csdn.net/shulianghan/article/details/41624613

1. Arithmetic Operators

arithmetic operators : Plus (+), minus (-), multiply (*), except (/), modulo (%), self-increment (+ +);

-- Other operations : if the square open operation is required, the method can be used in math.h;

Source code example :

/************************************************************************* > File name:10-arithmetic.m > Auth Or:octopus > Mail:octopus_truth.163.com > Created time: Day 11/30 17:54:01 2014 example of an arithmetic operator: subtraction *************** /#import <foundation/foundation.h>int Main (int ARGC, char * argv[]) {@autoreleasepool {//addition example Double A = 3.8;double b = 3.8;double sum = a + b; NSLog (@ "addition:%g", sum);//Subtraction Example Double sub = a-B; NSLog (@ "Subtraction:%g", sub);//multiply operation Double multi = A * b; NSLog (@ "multiplication:%g", multi);//division operation Double Divde = A/b; NSLog (@ "Division: Divide =%g", divde); NSLog (@ "Division: 3/0.0 =%g", 3/0.0); NSLog (@ "Division: -3/0.0 =%g", -3/0.0);//take remainder operation int c = 5;int d = 2;int mod = c% d; NSLog (@ "withdraw: MoD =%d", mod);//increment operation int e = c + + + 6; NSLog (@ "Self-increment: c =%d, E =%d", C, E);//The second-party calculation, called the MATH.H in the POW () method for the second-party calculation; double f = pow (A, 2); NSLog (@ "sub-square: F =%g", f);//compute square root int g = sqrt (4); NSLog (@ "square root: G =%d", g);//Gets the random number 5 or less int h = arc4random ()% 5;NSLog (@ "random number: H =%d", h);}} 

Execution Results:

Octopus-2:oc octopus$ clang-fobjc-arc-framework Foundation 10-arithmetic.m octopus-2:oc octopus$./a.out 2014-11-30 18:  22:24.786 a.out[3198:507] Addition: 7.62014-11-30 18:22:24.788 a.out[3198:507] Subtraction: 02014-11-30 18:22:24.789 a.out[3198:507] Multiplication : 14.442014-11-30 18:22:24.790 a.out[3198:507] Division: divide = 12014-11-30 18:22:24.790 a.out[3198:507] Division: 3/0.0 = Inf2 014-11-30 18:22:24.790 a.out[3198:507] Division: -3/0.0 =-inf2014-11-30 18:22:24.791 a.out[3198:507] Remainder: MoD = 12014-11-30 18 : 22:24.792 a.out[3198:507] Self-increment: c = 6, E = 112014-11-30 18:22:24.792 a.out[3198:507] Sub-party: F = 14.442014-11-30 18:22:24.79 3 a.out[3198:507] square root: G = 22014-11-30 18:22:24.793 a.out[3198:507] random number: H = 4

2. Assignment Operators

Assignment Analysis :

-- OC String Assignment : assigns the pointer to the OC string pointer, as shown in the following example;

-- C language String assignment : assigns a C string pointer to the C string pointer;

-- Continuous assignment : Successive assignments between multiple variables a = b = c = 38;

Source code example :

/*************************************************************************    > File name:10-assignment.m    > Author:octopus    > Mail:octopus_truth.163.com     > Created time: Day 11/30 21:32:18 2014 example of an assignment operator =  /#import <foundation/foundation.h  >int Main (int argc, char * argv[]) {@autoreleasepool {//assigns the STR string variable to the STR2 string variable nsstring *str = @ "Octopus";//oc string Assignment, Assign the pointer directly to the STR2 pointer nsstring *str2 = Str;char * str3 = "Han";//c string pointer assignment directly assigns pointer to Str4char * STR4 = str3;//print object-c string, hit printing without * pointer symbol, print OC type using%@ placeholder NSLog (@ "str2 =%@", str2); NSLog (@ "STR4 =%s", STR4);//continuous assignment int A, b, c;a = b = c = 38; NSLog (@ "A =%d, B =%d, c =%d", A, B, c);}}

Execution Results:

Octopus-2:oc octopus$ clang-fobjc-arc-framework Foundation 10-assignment.m octopus-2:oc octopus$ octopus-2:oc octopus$ ./a.out 2014-12-01 00:44:46.793 a.out[3695:507] str2 = octopus2014-12-01 00:44:46.795 a.out[3695:507] Str4 = han2014-12-0 1 00:44:46.795 a.out[3695:507] A = 38, B =.

3. Bitwise operators

data transfer binary:

- Positive : If the number is positive, follow the normal code;

negative numbers: The number is negative, in addition to the sign bit 1, the highest bit unchanged, the rest of the bitwise take back plus one;

-- negative numbers turn into binary numbers : complement form-1, followed by bitwise negation except for the highest bit;

Bitwise and (&) : One is 0, that is 0;

Bitwise OR (|) : One is 1, that is 1;

bitwise NON (~) : all values are reversed;

Bitwise XOR (^) : Different fetch 1, same fetch 0;

shift Left (<<) : Shift left, minimum bit 0, equal to 2 ^n;

shift Right (>>) : Move right, the highest bit fill symbol, equal to 2 ^ n;

code example :

/************************************************************************* > File name:10-bitoperation.m > Au Thor:octopus > Mail:octopus_truth.163.com > Created Time: 12/1 00:52:53 2014 *************************** /#import <foundation/foundation.h>int Main (int argc, char * argv[  ] {@autoreleasepool {//bitwise vs. & = 00NSLog (@ "1 & 2 =%d", 1 & 2),//bitwise-OR-11NSLog (@ "1 | 2 =%d", 1 | 2);/* Bitwise NON ~-5 source 10000000 00000000 00000000 00000101 Anti-code 11111111 11111111 11111111 11111010 (source bitwise reversed, highest bit unchanged) complement 111111 11 11111111 11111111 11111011 (complement is anti-code plus one) bitwise inverse result 1000 binary 4 */nslog (@ "~-5 =%d", ~-5);//Bitwise XOR (same 0, different 1) 011 ^ 101NSL OG (@ "3 ^ 6 =%d", 3 ^ 6);/* 5 shift left 2-bit 101 << 2 Results 10100 + 4 = */NSLog (@ "5 << 2 =%d", 5 << 2); /*-5 Shift left 2-5 complement is 11111111 11111111 11111111 11111011-5 left shift 11111111 11111111 11111111 11101100 complement minus 111,111,111 1111 1111 11111111 11101011 Take counter     10000000 00000000 00000000 00010100 The result is -20 */NSLog (@ "-5 << 2 =%d", 5 << 2);  /* Shift right, maximum bit-5 to right 2-5 complement 11111111 11111111 11111111 11111011 right shift 2 bit 11111111 11111111 11111111 11111110 minus 111,111,111 11111111 11111111 11111101 Inverse 10000000 00000000 00000000 00000010 The result is -2 */NSLog (@ "-5 >> 2 =%d", 5 >&gt ; 2);}}

Execution Result :

Octopus-2:oc octopus$ clang-fobjc-arc-framework Foundation 10-bitoperation.m octopus-2:oc octopus$ octopus-2:oc octopus$./a.out 2014-12-01 01:31:47.055 a.out[3813:507] 1 & 2 = 02014-12-01 01:31:47.057 a.out[3813:507] 1 | 2 = 32014-12-01 01:31:47.057 a.out[3813:507] ~-5 = 42014-12-01 01:31:47.058 a.out[3813:507] 3 ^ 6 = 52014-12-01 01:31:47. 058 a.out[3813:507] 5 << 2 = 202014-12-01 01:31:47.059 a.out[3813:507]-5 << 2 = -202014-12-01 01:31:47.059 A. OUT[3813:507]-5 >> 2 =-2

4. Comparison Operators

comparison Operation : The result is positive, 1 is true, 0 is false;

--= = Arithmetic : Compare numeric types, even if the types are different, the values are equal, then return true, 5.0 = = 5 the result is 1;

= = = Arithmetic : Compares numeric types, regardless of type, with unequal values, and returns false 0;

Source code example :

/*************************************************************************    > File name:10-compare.m    > Author:octopus    > Mail:octopus_truth.163.com     > Created Time: 12/1 01:35:57 2014 ******************* /#import <foundation/foundation.h>int Main (int argc, char * argv[]) {@autoreleasepool {///Only numeric comparisons are performed, only values are compared NSLog (@ "3 > 1 =%d", 3 > 1);//data types are different, but if the values are equal, return 1NSLog (@ "3 = = 3.0 =%d ", 3 = = 3.0); NSLog (@ "+ = = ' a ' =%d", + = ' a ');}}

Execution Result :

Octopus-2:oc octopus$ clang-fobjc-arc-framework Foundation 10-compare.m octopus-2:oc octopus$./a.out 2014-12-01 01:44: 56.099 a.out[3844:507] 3 > 1 = 12014-12-01 01:44:56.101 a.out[3844:507] 3 = = 3.0 = 12014-12-01 01:44:56.101 a.out[3844: 507] + = = ' a ' = 1

5. Logical Operators

logical Operation : The logical operation can only be a BOOL variable or constant in order to use the operator;

-- with Operation (&&) : True results are true;

-- or action (| |) : As long as one is true, the result is true;

-- non-operational (!) : Operand has one,! TRUE = FALSE;

-- xor operation (^) : The operand returns FALSE without returning TRUE;

code example :

/*************************************************************************    > File name:10-logic.m    > Author:octopus    > Mail:octopus_truth.163.com     > Created Time: 12/1 01:49:28 2014 ******************* /#import <foundation/foundation.h>int Main (int argc, char * argv[]) {@autoreleasepool {//Non 0 is TRUE, non-other number is Falsenslog (@ "!3 =%d",! 3); NSLog (@ "3 > 2 && ' 1 ' > ten =%d", 3 > 2 && ' 1 ' > 10); NSLog (@ "3 > 2 | | 2 > 3 =%d", 3 > 2 | | 2 > 3); NSLog (@ "3 > 2 ^ 3 > 2 =%d", 3 > 2 ^ 3 > 2);}}

Execution Result :

Octopus-2:oc octopus$ clang-fobjc-arc-framework Foundation 10-logic.m octopus-2:oc octopus$./a.out 2014-12-01 01:54:00 .282 a.out[3898:507]!3 = 02014-12-01 01:54:00.284 a.out[3898:507] 3 > 2 && ' 1 ' > 10 = 12014-12-01 01:54:00. 285 a.out[3898:507] 3 > 2 | | 2 > 3 = 12014-12-01 01:54:00.286 a.out[3898:507] 3 > 2 ^ 3 > 2 = 0

6. Comma operator

comma-expression : "Expression 1, expression 2 ... Expression n ", the result returns the value of the expression N;

code example :

/*************************************************************************    > File name:10-comma.m    > Author:octopus    > Mail:octopus_truth.163.com     > Created Time: 12/1 01:57:31 2014 ******************* /#import <foundation/foundation.h>int Main (int argc, char * argv[]) {@autoreleasepool {int a = (3, 3 > 2); NSLog (@ "a =%d", a), int b = (A = 3, a = 4, a = 5, a = 6); NSLog (@ "B =%d", b);}}

Execution Result :

Octopus-2:oc octopus$ clang-fobjc-arc-framework Foundation 10-comma.m 10-comma.m:13:12:warning:expression result Unus Ed [-wunused-value]                int a = (3, 3 > 2);                         ^1 warning Generated.octopus-2:oc octopus$./a.out 2014-12-01 02:00:06.466 a.out[3919:507] A = 12014-12-01 02:00:06.469 A. OUT[3919:507] B = 6

7. Three mesh operator

three mesh operator format : "Expression 1: Expression 2: Expression 3", if expression 1 is true, return the value of expression 2, expression 1 is false, return the value of expression 3;

Sample source code :

/*************************************************************************    > File name:10-three.m    > Author:octopus    > Mail:octopus_truth.163.com     > Created Time: 12/1 02:03:40 2014 ******************* /#import <foundation/foundation.h>int Main (int argc, char * argv[]) {@autoreleasepool {int a = 0; NSString *str = a? @ "A is true": @ "A is false"; NSLog (@ "%@", str);}}

Execution Effect:

Octopus-2:oc octopus$ clang-fobjc-arc-framework Foundation 10-three.m octopus-2:oc octopus$./a.out 2014-12-01 02:05:42 .389 a.out[3930:507] A is false

Blog Address : http://blog.csdn.net/shulianghan/article/details/41624613

The IOS development object-c operator