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

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Pointers

&：get address

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] ???
*/

---

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
*/

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?
}

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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

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

node *str = (node*)malloc(sizeof(int) + 32);

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;

---

void f(int x){
  ...;
}

void (*p)() = f;

---

#ifdef
//#ifundef
#else
#endif

用处：编译时 "-D xxx" 宏定义
（不需要修改源码）

#if (表达式)
#elif (表达式)

多段注释：

#if 0
sss
sss
#endif

恢复：
#if 1

#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
    }
}

---

void f(void){
  //没有参数
}

void g(){
  //任意参数
}

---

--save-temps：保存编译过程

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Note

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

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

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