1、数组
#import <Foundation/Foundation.h>
int arrays1[2];
int arrays2[] = {10,11};
int main(int argc, char *args[])
{
@autoreleasepool
{
NSLog(@"%d", arrays1[1]); // int初始数据的值为0
NSLog(@"%d", arrays2[1]); // 正常的存储
int len3 = 3;
NSString* arrays3[len3];
NSLog(@"%@", arrays3[0]);
char str2[] = {'I', ' ', 'L', 'o', 'v', 'e', ' ', 'y', 'o', 'u'};
char charArr1[2] = "12";
printf("====%s\n", charArr1);
}
}
2、函数
#import <Foundation/Foundation.h>
#import "4_impFunc.h"
int main(int argc, char* args[])
{
@autoreleasepool
{
NSLog(@"out count=%d", count);
change();
NSLog(@"out count=%d", count);
printf("%d\n", add(1,2));
printf("%d\n", add(3,4));
printf("%d\n", add(5,6));
}
}
3、引用
int add(int, int);
void change();
int count;
#import <Foundation/Foundation.h>
int count = 1;
int add(int a, int b)
{
static int varAdd = 10;
NSLog(@"change, varAdd=%d", varAdd);
varAdd++;
return a + b;
}
void change()
{
NSLog(@"change, count=%d", count++);
}
4、define
#import <Foundation/Foundation.h>
#define PI 3.1415926
#define GIRTH(r) PI * 2 * (r)
#define AREA(r) PI * r * (r)
int main(int argc, char* args[])
{
@autoreleasepool
{
NSLog(@"please input radius:");
double radius;
scanf("%lg", &radius);
NSLog(@"图周长: %g", GIRTH(radius));
NSLog(@"图面积: %g", AREA(radius));
}
}
5、指针
#import <Foundation/Foundation.h>
int main(int argc, char* args[])
{
@autoreleasepool
{
void swap(int*, int*);
void copyStr(char*, char*);
int maxNum(int*, int);
int avgNum(int*, int);
int a = 10;
int b = 11;
int* p1 = &a;
int* p2 = &b;
NSLog(@"before p1=%d, p2=%d", *p1, *p2);
swap(p1, p2);
NSLog(@"after p1=%d, p2=%d", *p1, *p2);
int arr1[] = {1,2,3};
for(int i = 0; i < sizeof(arr1) / sizeof(arr1[0]); i++)
{
NSLog(@"用最原始的办法遍历arr1 %d = %d", i, *(arr1 + i));
}
int arr2[] = {4,5,6,7};
for(int* p = arr1, len = sizeof(arr1) / sizeof(arr1[0]); p < arr1 + len; p++)
{
NSLog(@"用指针的办法遍历arr1 %d", *p);
}
// 字符串复制
char* str1 = "heheda";
char str2[20];
copyStr(str2, str1);
NSLog(@"str2=%s", str2);
// 指针调用函数
int data[] = {1,3,2,9,8};
int (*fnpt)();
fnpt = maxNum;
NSLog(@"maxValue = %d", (*fnpt)(data, 5));
fnpt = avgNum;
NSLog(@"maxValue = %d", (*fnpt)(data, 5));
}
}
void swap(int* p1, int* p2)
{
int tmp = *p2;
*p2 = *p1;
*p1 = tmp;
}
void copyStr(char* to, char* from)
{
while(*from)
{
// NSLog(@"from=%c", *from);
*to = *from;
to++;
from++;
}
*to = '\0';
}
int maxNum(int* dataArray, int len)
{
int maxValue = *dataArray;
for(int* p = dataArray; p < dataArray + len; p++)
{
if(*p > maxValue)
{
maxValue = *p;
}
}
return maxValue;
}
int avgNum(int* dataArray, int len)
{
int count = 0;
for(int* p = dataArray; p < dataArray + len; p++)
{
count += *p;
}
return count / len;
}
7、结构体
#import <Foundation/Foundation.h>
int main(int argc, char* args[])
{
@autoreleasepool
{
struct
{
int x;
int y;
} p1;
struct POINT
{
int x1;
int x2;
};
struct POINT p2;
p1.x = 1;
NSLog(@"p1.x = %d", p1.x);
typedef struct POINT PPP;
PPP p3;
p3.x1 = 1001;
NSLog(@"p3.x1=%d", p3.x1);
}
}
8、block
#import <Foundation/Foundation.h>
typedef int (^Process)(int);
void processArray(int*, int, Process);
int main(int argc, char* args[])
{
@autoreleasepool
{
void (^printStr)() = ^()
{
NSLog(@"this is printStr block");
};
printStr();
double (^hybot)(double, double) = ^ double (double num1, double num2)
{
return sqrt(num1 * num1 + num2 * num2);
};
NSLog(@"hybot=%f",hybot(1,2));
// 不可修改
int val1 = 10;
void (^printMy)() = ^()
{
NSLog(@"printMy val1 = %d", val1);
int iValue111 = 11;
NSLog(@"printMy iValue111 = %d", iValue111);
};
printMy();
// 可以修改
__block int val2 = 20;
void (^printYou)() = ^()
{
NSLog(@"printYou val2 = %d", val2);
val2 = 21;
NSLog(@"printYou val2 = %d", val2);
};
val2 = 22;
printYou();
NSLog(@"printYou val2 = %d", val2);
// 块作为函数参数. 我理解是抽象类的作法
int array1[3] = {2,5,9};
processArray(array1, 3, ^(int num)
{
return num * num;
});
}
}
void processArray(int* dataArray, int len, Process process)
{
for(int* p = dataArray; p < dataArray + len; p++)
{
NSLog(@"result is %d", process(*p));
}
}
9、hello world
#import <Foundation/Foundation.h>
int main(int argc, char *args[]) {
@autoreleasepool {
NSLog(@"Hello World my Object-C");
long long b = 6440940218;
NSLog(@"===%ld=====", (long) b);
NSString *str1 = @"this is object-c string";
NSLog(@"===%@===", str1);
NSDate *date1 = [NSDate date];
NSLog(@"====%@", date1);
char char1 = 'a';
char char2 = '\n';
char char3 = 98;
NSLog(@"==%d==%c==%c", char1, char2, char3);
// 默认只保留6位小数. 需要时再指定
double d1 = 12.345678901;
NSLog(@"====%2.8f", d1);
// 无穷大
NSLog(@"====%g", 5 / 0.0);
// 枚举， 本质就是无符号整型unsign int
enum season {spring, summer, fall, winter};
enum season s1 = spring;
enum season s2 = summer;
enum season s3 = fall;
enum season s4 = winter;
NSLog(@"====%u, %u, %u, %u", s1, s2, s3, s4);
// BOOL在OC底层是unsign int, 只占1个字节. 所以给它大的话, 得到的结果不一定是YES
BOOL b1 = 254;
BOOL b2 = 1;
NSLog(@"%d", b1 > b2);
NSLog(@"===%d", (short) 33000);
NSLog(@"===%d", (int) 32768);
}
return 0;
}
