发表更新Cate3 分钟读完 (大约416个字)

程设

排序

快速排序的两个分区方法：$Lomuto$ 单指针，$Hoare$ 双指针

归并排序在多核情境更快 —— 均分

Pointers

&：get address

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int i = 10;
printf("%d\n", i);
printf("%p\n", &i);

/* %X, %x, %lu
%p 64bit
%x 32bit(不完整)
*/

/* 
printf("%p\n", &(i + 1)); 报错
左值：可以出现在赋值号左侧的值
    a = 6 √
    (a + 1) = 6 ×
    a # 2 = a[2] ???
*/
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int a[3] = {0, 1, 2};
printf("%p\n", &a[0]);
printf("%p\n", &a[1]);
printf("%p\n", &a[2]);
printf("%p\n", &a); //equal to a[0]
/*

*/
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int i = 10;
int *p = &i;
printf("%p\n", p);
printf("%d\n", *p); //访问变量，*p可作左值9

int *x, *y; //with each one

/*
access: r & w
*/
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vp  oid f(int *a){

}

void g(int a[]){

}

//equal

int main(){
    int a[10];
    printf("%p\n", a);
    printf("%p\n", &a);
    //equal

    int *p = a;
    printf("%d\n", p[0]);
    printf("%d\n", *a);
    printf("%d\n", *(p + 5));
    printf("%d\n", p - a); // 1?
}

string.h下的函数：

  • strlen(char *)
  • strcmp
  • strcpy

while(*p++) 可以在字符串末结束

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struct{
    int a;
}str;

这样是可以的

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struct node{
    int len;
    char content[];
};

node *str = (node*)malloc(sizeof(int) + 32);
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typedef struct{
  ...
}node;

node t;


typedef struct node{//声明
  ...
  node *next;
}node;

typedef char line[30]
line aa;p //char aa[30]

typedef int *inp
inp p;
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void f(int x){
  ...;
}

void (*p)() = f;
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#ifdef
//#ifundef
#else
#endif

用处：编译时 "-D xxx" 宏定义
（不需要修改源码）
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#if (表达式)
#elif (表达式)
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多段注释：

#if 0
sss
sss
#endif

恢复：
#if 1
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#error text...
让编译器出错
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if(){
    int i;//第一个
    if(){
        int i;//第二个，此if内优先访问此i
    }
}
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void f(void){
  //没有参数
}

void g(){
  //任意参数
}
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--save-temps：保存编译过程

Note

1.Declaring the pointer of a function within another function’s prototype declaration：

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int func( int x, int (*func2)(int, double) )

However, another way int func2(int, double) is acceptable too, for the function type can be automatically converted to function pointer type

发表更新Cate2 分钟读完 (大约252个字)

py笔记

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######

print(0b100)  # 二进制整数
print(0o100)  # 八进制整数
print(100)    # 十进制整数
print(0x100)  # 十六进制整数

######

print(type(100))  # <class 'int'>
print(type(123.45))  # <class 'float'>
print(type('hello, world'))  # <class 'str'>
print(type(True))  # <class 'bool'>

######

print(int('100', base=16))  # str->十六进制int
print(bool(1))          # str->bool，True
print(chr(65))           # int->str，输出'd'
print(ord('A'))         # str->int，100

######

print(11//3)
print(2 ** 4)

######

a = None
print(a := 10)
print(1 <= a <= 2)

b = 11

print('%d 你好 %d' % (a, b))
print(f'{a:d} 你好 {b:.1f}')

######

if 1 <= a <= 100:
    print('你好')
elif a and (not b):
    print('你好1')
else:
    if b:
        print('wow')
    else:
        print('now')

match a:
    case 1 | 3: print('1')
    case 2: print('2')

######

'''

import time

        # 0 ~ 99

for _ in range (100): # empty, only repeat
    time.sleep(1) # 1s

for i in range (0, 100, 2): # even number
    time.sleep(0.01)

print(sum(range(1, 3, 0.1)))

'''

######

while a <= 15:
    a += 1
    if a > 20:
        break
    elif a > 25:
        continue

######

import random

a = random.randrange(1, 101)

######

items1 = [1, 1.1, '1', True]
items2 = list(range(1, 11))
items3 = list('hello') # h e l l o
print(items1 + items2 + items3 * 2)
print(2 not in items1) # False
print(items1[0], items1[-1]) # forward subscript 0 ~ 4 is equal to reversed subscript -5 ~ -1
print(items1[0:5:2]) # range [0,5), span is 2, namely 0, 2, 4, they can also be negative
print(items1[:], items1[::]) # acquiescently 0, ending, 1
# such options can also be used to modify lists

# lists can be compared, like ==, !=, <= ..., the rule is comparing each elements one by one(parallel[adv])


# type 1 to traverse each one:
for i in range(len(items1)):
    print(items1[i], end = ' ')
# type 2:
for item in items1:
    print(item, end = " ")


######

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