C 语言复习提纲

#include <stdio.h>

// 定义一个结构体
struct Person {
    char name[20];
    int age;
    float height;
};

int main() {
    // 声明一个结构体变量并初始化
    struct Person person1 = {"Alice", 25, 1.75};
    
    // 访问结构体成员并打印信息
    printf("Person's name: %s\n", person1.name);       // Person's name: Alice
    printf("Person's age: %d\n", person1.age);         // Person's age: 25
    printf("Person's height: %.2f\n", person1.height); // Person's height: 1.75
    
    return 0;
}

#include <stdio.h>

// 定义一个联合
union Data {
    int i;
    float f;
    char str[20];
};

int main() {
    // 声明一个联合变量并使用
    union Data data;
    
    data.i = 10;
    printf("data.i: %d\n", data.i);   // data.i: 10
    
    data.f = 3.14; // 覆盖整型成员，为浮点型成员赋值
    printf("data.f: %.2f\n", data.f); // data.f: 3.14
    
    printf("data.i after changing data.f: %d\n", data.i);
    // data.i after changing data.f: 1078523331
    
    return 0;
}

int a = 5;
int b = 10;
int sum = a + b; // 顺序执行，计算a和b的和

int x = 15;
if (x > 10) {
  printf("x大于10\n");
} else {
  printf("x不大于10\n");
}

int day = 3;
switch (day) {
  case 1:
    printf("星期一\n");
    break;
  case 2:
    printf("星期二\n");
    break;
  default:
    printf("其他天\n");
}

// while循环
int i = 0;
while (i < 5) {
  printf("%d\n", i);
  i++;
}

int j = 0;
do {
  printf("%d\n", j);
  j++;
} while (j < 5);

for (int k = 0; k < 5; k++) {
  printf("%d\n", k);
}

for (int m = 0; m < 10; m++) {
  if (m == 5) {
    break; // 当m等于5时跳出循环
  }
  printf("%d\n", m);
}

for (int n = 0; n < 5; n++) {
  if (n == 2) {
    continue; // 当n等于2时跳过当前迭代
  }
  printf("%d\n", n);
}

int number = 0;
loop: // 标签
if (number < 5) {
  printf("%d\n", number);
  number++;
  goto loop; // 跳转到标签loop处
}

int fa[] = {};
int a[10];

// int a[];
// error: 不允许使用不完整的类型

int b[2] = {};

// int b[2] = {1, 2, 3};
// error: 初始值设定项太多

int c[][5] = {{1, 2}, {1}};

// int c[][2] = {{1, 2, 3}};
// error: 初始值设定项太多

// int c[5][];
// error: 数组不能包含此类型的元素

  int f[] = {10, 20};
  printf("%x %d %d\n", f, f[0], *f);
  // 52bffb08 10 10
  printf("%x %d %d\n", f + 1, f[1], *(f + 1));
  // 52bffb0c 20 20
  printf("%x %d %d\n", (void *)f + 1, f[1], *(int *)((void *)f + 1));
  // 52bffb09 20 335544320

void fun(int p[4][2])
{
  for (int i = 0; i < 4; i++)
  {
  for (int j = 0; j < 2; j++)
    printf("%d ", p[i][j]);
  printf("\n");
  }
}

int a[3][2] = {1, 2, 3, 4, 5, 6};
int b[3][1], c[3][3];
fun(a);
// 1 2 
// 3 4
// 5 6
// -1475524368 371
// 超出的内容会直接溢出

// fun(b);
// cannot convert 'int (*)[1]' to 'int (*)[2]'

// fun(c);
// cannot convert 'int (*)[3]' to 'int (*)[2]'

void bubbleSort(int arr[], int n) {
  for (int i = 0; i < n - 1; i++) {
    for (int j = 0; j < n - i - 1; j++) {
      if (arr[j] > arr[j + 1]) {
        int temp = arr[j];
        arr[j] = arr[j + 1];
        arr[j + 1] = temp;
      }
    }
  }
}

void selectionSort(int arr[], int n) {
  int minIndex;
  for (int i = 0; i < n - 1; i++) {
    minIndex = i;
    for (int j = i + 1; j < n; j++) {
      if (arr[j] < arr[minIndex]) {
        minIndex = j;
      }
    }
    int temp = arr[i];
    arr[i] = arr[minIndex];
    arr[minIndex] = temp;
  }
}

void insertionSort(int arr[], int n) {
  int key, j;
  for (int i = 1; i < n; i++) {
    key = arr[i];
    j = i - 1;
    while (j >= 0 && arr[j] > key) {
      arr[j + 1] = arr[j];
      j = j - 1;
    }
    arr[j + 1] = key;
  }
}

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main() {
  int i, n;
  // 设置随机数种子
  srand(time(0));

  n = rand();      // 生成随机数
  n = rand() % 10; // 生成0到10之间的随机数
  
  return 0;
}

#include <stdio.h>
#include <stdlib.h>

struct Node {
  int data;
  struct Node* next;
};

void append(struct Node* head , int data) {
  struct Node* p = head;
  struct Node* new_node = (struct Node*)malloc(sizeof(struct Node));
  new_node->data = data;
  new_node->next = NULL;

  while (p->next != NULL) {
    p = p->next;
  }
  p->next = new_node;
}