使用GPT 3.5 学习C语言: 25个简单代码

README.md

@@ -16,6 +16,10 @@ C/C++零基础入门 系列教程 不懂英文 从零开始
 ### C/CPP零基础入门编程软件资源
 https://wwcz.lanzout.com/b01urh63a   密码:7q5c
 
+
 - `算法动画图解_中文欢乐版.apk`  视频右侧的 算法动画图解 程序
 - `MSVC2015Mini.7z`    视频中 VSCODE 调用的 C/C++ 编译器
 
+## [使用GPT 3.5 学习C语言: 25个简单代码让你了解 C 语言基本语法](./base/)
+
+## [C/C++零基础入门 学习收集的示例代码](./examples/)

base/01-hello.c

@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int main() {
+    printf("Hello, World!\n");
+    return 0;
+}

base/02-Variables.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+
+int main() {
+  int age = 20;
+  float weight = 65.5;
+  char grade = 'A';
+  printf("Age: %d\n", age);
+  printf("Weight: %.2f\n", weight);
+  printf("Grade: %c\n", grade);
+  return 0;
+}

base/03-stdio.c

@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int main() {
+    int num;
+    printf("Enter a number: ");
+    scanf("%d", &num);
+    printf("You entered: %d\n", num);
+    return 0;
+}

base/04-if-else.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+int main() {
+  int num;
+  printf("Enter a number: ");
+  scanf("%d", &num);
+  if (num > 0) {
+    printf("Positive number\n");
+  } else if (num < 0) {
+    printf("Negative number\n");
+  } else {
+    printf("Zero\n");
+  }
+  return 0;
+}

base/05-for-while.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+int main() {
+  for (auto i = 1; i <= 8; i++)
+    printf("%d ", i);
+
+  int j = 8;
+  while (j > 0)
+    printf("%d ", j--);
+
+  int k = 1;
+  do {
+    printf("%d ", k++);
+  } while (k <= 8);
+
+  return 0;
+}

base/06-array.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+int main() {
+  int numbers[5] = {1, 2, 3, 4, 5};
+  printf("First element: %d\n", numbers[0]);
+  printf("Second element: %d\n", numbers[1]);
+
+  for (int i = 0; i < 5; i++) {
+    printf("%d ", numbers[i]);
+  }
+  return 0;
+}

base/07-fun.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+
+int add(int a, int b) { 
+    return a + b; 
+}
+
+int main() {
+  int result = add(2, 3);
+  printf("Result: %d\n", result);
+  return 0;
+}

base/08-char-string.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+
+int main() {
+  char name[20] = "John Doe";
+  printf("Name: %s\n", name);
+
+  char message[50];
+  printf("Enter a message: ");
+  fgets(message, sizeof(message), stdin);
+  printf("You entered: %s\n", message);
+
+  return 0;
+}

base/09-struct.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+typedef struct {
+  char name[20];
+  int age;
+} Person;
+
+int main() {
+  Person person;
+  strcpy(person.name, "John Doe");
+  person.age = 25;
+
+  printf("Name: %s\n", person.name);
+  printf("Age: %d\n", person.age);
+
+  return 0;
+}

base/10-pointer.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+
+int main() {
+  int num = 10;
+  int *ptr = &num;
+
+  printf("Value: %d\n", num);
+  printf("Address: %p\n", &num);
+  printf("Pointer value: %p\n", ptr);
+  printf("Dereference pointer: %d\n", *ptr);
+
+  return 0;
+}

base/11-file.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int main() {
+  FILE *file = fopen("file.txt", "w");
+  if (file != NULL) {
+    fprintf(file, "This is some text.");
+    fclose(file);
+    printf("File created and written successfully.\n");
+  } else {
+    printf("Error opening file.\n");
+  }
+
+  return 0;
+}

base/12-enum.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+
+typedef enum {
+  MONDAY,
+  TUESDAY,
+  WEDNESDAY,
+  THURSDAY,
+  FRIDAY,
+  SATURDAY,
+  SUNDAY
+} Day;
+
+int main() {
+  Day today = TUESDAY;
+
+  switch (today) {
+  case MONDAY:
+    printf("It's Monday.\n");
+    break;
+  case TUESDAY:
+    printf("It's Tuesday.\n");
+    break;
+  case WEDNESDAY:
+    printf("It's Wednesday.\n");
+    break;
+  case THURSDAY:
+    printf("It's Thursday.\n");
+    break;
+  case FRIDAY:
+    printf("It's Friday.\n");
+    break;
+  case SATURDAY:
+    printf("It's Saturday.\n");
+    break;
+  case SUNDAY:
+    printf("It's Sunday.\n");
+    break;
+  }
+
+  return 0;
+}

base/12-malloc.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main() {
+  int *numbers = (int *)malloc(5 * sizeof(int));
+  if (numbers != NULL) {
+    numbers[0] = 1;
+    numbers[1] = 2;
+    numbers[2] = 3;
+    numbers[3] = 4;
+    numbers[4] = 5;
+
+    int i;
+    for (i = 0; i < 5; i++) {
+      printf("%d ", numbers[i]);
+    }
+
+    free(numbers);
+  } else {
+    printf("Memory allocation failed.\n");
+  }
+
+  return 0;
+}

base/13-enum.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+
+typedef enum {
+  MONDAY,
+  TUESDAY,
+  WEDNESDAY,
+  THURSDAY,
+  FRIDAY,
+  SATURDAY,
+  SUNDAY
+} Day;
+
+int main() {
+  Day today = TUESDAY;
+
+  switch (today) {
+  case MONDAY:
+    printf("It's Monday.\n");
+    break;
+  case TUESDAY:
+    printf("It's Tuesday.\n");
+    break;
+  case WEDNESDAY:
+    printf("It's Wednesday.\n");
+    break;
+  case THURSDAY:
+    printf("It's Thursday.\n");
+    break;
+  case FRIDAY:
+    printf("It's Friday.\n");
+    break;
+  case SATURDAY:
+    printf("It's Saturday.\n");
+    break;
+  case SUNDAY:
+    printf("It's Sunday.\n");
+    break;
+  }
+
+  return 0;
+}

base/14-recursion.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+int factorial(int n) {
+  if (n <= 1) {
+    return 1;
+  } else {
+    return n * factorial(n - 1);
+  }
+}
+
+int main() {
+  int num = 5;
+  int result = factorial(num);
+  printf("Factorial of %d is %d.\n", num, result);
+
+  return 0;
+}

base/15-multiple-files.c

@@ -0,0 +1,20 @@
+// 15.多文件编程
+// file1.c
+#include <stdio.h>
+
+void sayHello() { 
+  printf("Hello from file1.c!\n"); 
+}
+
+// file2.c
+#include <stdio.h>
+
+void sayHello(); // 函数声明
+
+int main() {
+  sayHello();
+  return 0;
+}
+
+// 编译和链接两个文件：
+// gcc file1.c file2.c -o program

base/16-nodes.c

@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct Node {
+  int data;
+  struct Node *next;
+} Node;
+
+void insert(Node **head, int data) {
+  Node *newNode = (Node *)malloc(sizeof(Node));
+  newNode->data = data;
+  newNode->next = NULL;
+
+  if (*head == NULL) {
+    *head = newNode;
+  } else {
+    Node *temp = *head;
+    while (temp->next != NULL) {
+      temp = temp->next;
+    }
+    temp->next = newNode;
+  }
+}
+
+void display(Node *head) {
+  Node *temp = head;
+  while (temp != NULL) {
+    printf("%d ", temp->data);
+    temp = temp->next;
+  }
+  printf("\n");
+}
+
+int main() {
+  Node *head = NULL;
+  insert(&head, 1);
+  insert(&head, 2);
+  insert(&head, 3);
+  display(head);
+
+  return 0;
+}

base/17-ptr-fun.c

@@ -0,0 +1,19 @@
+#include <stdio.h>
+
+int add(int a, int b) { 
+  return a + b; }
+
+int subtract(int a, int b) { 
+  return a - b; }
+
+int main() {
+  int (*ptr)(int, int);
+
+  ptr = add;
+  printf("Addition: %d\n", ptr(2, 3));
+
+  ptr = subtract;
+  printf("Subtraction: %d\n", ptr(5, 3));
+
+  return 0;
+}

base/18-bits-logic.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+
+int main() {
+  unsigned int a = 5; // 0000 0101
+  unsigned int b = 3; // 0000 0011
+
+  unsigned int result;
+
+  result = a & b; // 0000 0001 (位与)
+  printf("Bitwise AND: %u\n", result);
+
+  result = a | b; // 0000 0111 (位或)
+  printf("Bitwise OR: %u\n", result);
+
+  result = a ^ b; // 0000 0110 (位异或)
+  printf("Bitwise XOR: %u\n", result);
+
+  result = ~a; // 1111 1010 (位取反)
+  printf("Bitwise NOT: %u\n", result);
+
+  result = a << 2; // 0001 0100 (左移)
+  printf("Left Shift: %u\n", result);
+
+  result = a >> 1; // 0000 0010 (右移)
+  printf("Right Shift: %u\n", result);
+
+  return 0;
+}

base/19-define.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+
+#define PI 3.14159
+#define SQUARE(x) ((x) * (x))
+
+int main() {
+    float radius = 2.5;
+    float area = PI * SQUARE(radius);
+    
+    printf("Area: %.2f\n", area);
+    
+    return 0;
+}

base/20-errno.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+
+int main() {
+    FILE *file = fopen("nonexistent.txt", "r");
+    if (file == NULL) {
+        printf("Error opening file: %s\n", strerror(errno));
+    } else {
+        // 文件操作
+        fclose(file);
+    }
+    
+    return 0;
+}

base/21-bit-field.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+
+struct Flags {
+    unsigned int isRed : 1;
+    unsigned int isGreen : 1;
+    unsigned int isBlue : 1;
+};
+
+int main() {
+    struct Flags f;
+    f.isRed = 1;
+    f.isGreen = 0;
+    f.isBlue = 1;
+    
+    printf("Red: %u\n", f.isRed);
+    printf("Green: %u\n", f.isGreen);
+    printf("Blue: %u\n", f.isBlue);
+    
+    return 0;
+}

base/22-type-conver.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+int main() {
+    int a = 10;
+    double b = 3.14;
+    
+    double result = (double)a + b;
+    
+    printf("Result: %.2f\n", result);
+    
+    return 0;
+}

base/23-fun-arg.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+void greet(char *name, char *message) {
+  if (name == NULL) {
+    name = "Guest";
+  }
+  printf("Hello, %s! %s\n", name, message);
+}
+
+int main() {
+  greet(NULL, "Welcome to the program.");
+  greet("John", "Nice to meet you.");
+
+  return 0;
+}

base/24-struct-arrow.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct {
+  int x;
+  int y;
+} Point;
+
+int main() {
+  Point *p = (Point *)malloc(sizeof(Point));
+  p->x = 2;
+  p->y = 3;
+
+  printf("x: %d\n", p->x);
+  printf("y: %d\n", p->y);
+
+  free(p);
+
+  return 0;
+}

base/25-comma.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int main() {
+  int a = 2, b = 3, c = 4, result;
+
+  result = (a * b) + (c - a), a++, b++, c++;
+
+  printf("Result: %d\n", result);
+  printf("a: %d\n", a);
+  printf("b: %d\n", b);
+  printf("c: %d\n", c);
+
+  return 0;
+}

base/README.md

@@ -0,0 +1,605 @@
+## 使用GPT 3.5 学习C语言: 25个简单代码让你了解 C 语言基本语法
+
+![](https://lyvba.com/wp-content/uploads/2023/09/C_CPP零基础入门.jpg)
+
+### 以下是一些学习C语言的常用代码示例，涵盖了各种语法和概念：
+
+  1. Hello World
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    printf("Hello, World!\n");
+    return 0;
+    }
+
+  2. 变量和数据类型
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    int age = 20;
+    float weight = 65.5;
+    char grade = 'A';
+    printf("Age: %d\n", age);
+    printf("Weight: %.2f\n", weight);
+    printf("Grade: %c\n", grade);
+    return 0;
+    }
+
+  3. 输入输出
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    int num;
+    printf("Enter a number: ");
+    scanf("%d", &num);
+    printf("You entered: %d\n", num);
+    return 0;
+    }
+
+  4. 条件语句
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    int num;
+    printf("Enter a number: ");
+    scanf("%d", &num);
+    if (num > 0) {
+        printf("Positive number\n");
+    } else if (num < 0) {
+        printf("Negative number\n");
+    } else {
+        printf("Zero\n");
+    }
+    return 0;
+    }
+
+  5. 循环语句
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    int i;
+    for (i = 1; i <= 5; i++) {
+        printf("%d ", i);
+    }
+    printf("\n");
+    
+    int j = 1;
+    while (j <= 5) {
+        printf("%d ", j);
+        j++;
+    }
+    printf("\n");
+    
+    int k = 1;
+    do {
+        printf("%d ", k);
+        k++;
+    } while (k <= 5);
+    printf("\n");
+    
+    return 0;
+    }
+
+  6. 数组
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    int numbers[5] = {1, 2, 3, 4, 5};
+    printf("First element: %d\n", numbers[0]);
+    printf("Second element: %d\n", numbers[1]);
+    
+    int i;
+    for (i = 0; i < 5; i++) {
+        printf("%d ", numbers[i]);
+    }
+    printf("\n");
+    
+    return 0;
+    }
+
+希望以上代码示例能帮助你学习C语言的基础知识。请注意，这只是一小部分C语言的语法示例，还有很多其他的语法和概念等待你去探索和学习。
+
+当然，以下是更多的C语言代码示例，涵盖了更多的语法和概念：
+
+  7. 函数
+
+    
+    
+    #include <stdio.h>
+    
+    int add(int a, int b) {
+    return a + b;
+    }
+    
+    int main() {
+    int result = add(2, 3);
+    printf("Result: %d\n", result);
+    return 0;
+    }
+
+  8. 字符串
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    char name[20] = "John Doe";
+    printf("Name: %s\n", name);
+    
+    char message[50];
+    printf("Enter a message: ");
+    fgets(message, sizeof(message), stdin);
+    printf("You entered: %s\n", message);
+    
+    return 0;
+    }
+
+  9. 结构体
+
+    
+    
+    #include <stdio.h>
+    
+    typedef struct {
+    char name[20];
+    int age;
+    } Person;
+    
+    int main() {
+    Person person;
+    strcpy(person.name, "John Doe");
+    person.age = 25;
+    
+    printf("Name: %s\n", person.name);
+    printf("Age: %d\n", person.age);
+    
+    return 0;
+    }
+
+  10. 指针
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    int num = 10;
+    int *ptr = &num;
+    
+    printf("Value: %d\n", num);
+    printf("Address: %p\n", &num);
+    printf("Pointer value: %p\n", ptr);
+    printf("Dereference pointer: %d\n", *ptr);
+    
+    return 0;
+    }
+
+  11. 文件操作
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    FILE *file = fopen("file.txt", "w");
+    if (file != NULL) {
+        fprintf(file, "This is some text.");
+        fclose(file);
+        printf("File created and written successfully.\n");
+    } else {
+        printf("Error opening file.\n");
+    }
+    
+    return 0;
+    }
+
+以上示例涵盖了C语言中的一些常用语法和概念，希望对你的学习有所帮助。记得不断练习和探索，以加深对C语言的理解和掌握。
+
+当然，以下是更多的C语言代码示例，涵盖了更多的语法和概念：
+
+  12. 动态内存分配
+
+    
+    
+    #include <stdio.h>
+    #include <stdlib.h>
+    
+    int main() {
+    int *numbers = (int *)malloc(5 * sizeof(int));
+    if (numbers != NULL) {
+        numbers[0] = 1;
+        numbers[1] = 2;
+        numbers[2] = 3;
+        numbers[3] = 4;
+        numbers[4] = 5;
+    
+        int i;
+        for (i = 0; i < 5; i++) {
+            printf("%d ", numbers[i]);
+        }
+    
+        free(numbers);
+    } else {
+        printf("Memory allocation failed.\n");
+    }
+    
+    return 0;
+    }
+
+  13. 枚举
+
+    
+    
+    #include <stdio.h>
+    
+    typedef enum {
+    MONDAY,
+    TUESDAY,
+    WEDNESDAY,
+    THURSDAY,
+    FRIDAY,
+    SATURDAY,
+    SUNDAY
+    } Day;
+    
+    int main() {
+    Day today = TUESDAY;
+    
+    switch (today) {
+        case MONDAY:
+            printf("It's Monday.\n");
+            break;
+        case TUESDAY:
+            printf("It's Tuesday.\n");
+            break;
+        case WEDNESDAY:
+            printf("It's Wednesday.\n");
+            break;
+        case THURSDAY:
+            printf("It's Thursday.\n");
+            break;
+        case FRIDAY:
+            printf("It's Friday.\n");
+            break;
+        case SATURDAY:
+            printf("It's Saturday.\n");
+            break;
+        case SUNDAY:
+            printf("It's Sunday.\n");
+            break;
+    }
+    
+    return 0;
+    }
+
+  14. 递归
+
+    
+    
+    #include <stdio.h>
+    
+    int factorial(int n) {
+    if (n <= 1) {
+        return 1;
+    } else {
+        return n * factorial(n - 1);
+    }
+    }
+    
+    int main() {
+    int num = 5;
+    int result = factorial(num);
+    printf("Factorial of %d is %d.\n", num, result);
+    
+    return 0;
+    }
+
+  15. 多文件编程
+
+file1.c:
+
+    
+    
+    #include <stdio.h>
+    
+    void sayHello() {
+    printf("Hello from file1.c!\n");
+    }
+
+file2.c:
+
+    
+    
+    #include <stdio.h>
+    
+    void sayHello(); // 函数声明
+    
+    int main() {
+    sayHello();
+    return 0;
+    }
+
+编译和链接两个文件：
+
+    
+    
+    gcc file1.c file2.c -o program
+
+以上示例涵盖了C语言中的更多语法和概念，希望对你的学习有所帮助。记得不断练习和探索，以加深对C语言的理解和掌握。
+
+当然，以下是更多的C语言代码示例，涵盖了更多的语法和概念：
+
+  16. 链表
+
+    
+    
+    #include <stdio.h>
+    #include <stdlib.h>
+    
+    typedef struct Node {
+    int data;
+    struct Node *next;
+    } Node;
+    
+    void insert(Node **head, int data) {
+    Node *newNode = (Node *)malloc(sizeof(Node));
+    newNode->data = data;
+    newNode->next = NULL;
+    
+    if (*head == NULL) {
+        *head = newNode;
+    } else {
+        Node *temp = *head;
+        while (temp->next != NULL) {
+            temp = temp->next;
+        }
+        temp->next = newNode;
+    }
+    }
+    
+    void display(Node *head) {
+    Node *temp = head;
+    while (temp != NULL) {
+        printf("%d ", temp->data);
+        temp = temp->next;
+    }
+    printf("\n");
+    }
+    
+    int main() {
+    Node *head = NULL;
+    insert(&head, 1);
+    insert(&head, 2);
+    insert(&head, 3);
+    display(head);
+    
+    return 0;
+    }
+
+  17. 函数指针
+
+    
+    
+    #include <stdio.h>
+    
+    int add(int a, int b) {
+    return a + b;
+    }
+    
+    int subtract(int a, int b) {
+    return a - b;
+    }
+    
+    int main() {
+    int (*ptr)(int, int);
+    
+    ptr = add;
+    printf("Addition: %d\n", ptr(2, 3));
+    
+    ptr = subtract;
+    printf("Subtraction: %d\n", ptr(5, 3));
+    
+    return 0;
+    }
+
+  18. 位运算
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    unsigned int a = 5; // 0000 0101
+    unsigned int b = 3; // 0000 0011
+    
+    unsigned int result;
+    
+    result = a & b; // 0000 0001 (位与)
+    printf("Bitwise AND: %u\n", result);
+    
+    result = a | b; // 0000 0111 (位或)
+    printf("Bitwise OR: %u\n", result);
+    
+    result = a ^ b; // 0000 0110 (位异或)
+    printf("Bitwise XOR: %u\n", result);
+    
+    result = ~a; // 1111 1010 (位取反)
+    printf("Bitwise NOT: %u\n", result);
+    
+    result = a << 2; // 0001 0100 (左移)
+    printf("Left Shift: %u\n", result);
+    
+    result = a >> 1; // 0000 0010 (右移)
+    printf("Right Shift: %u\n", result);
+    
+    return 0;
+    }
+
+  19. 宏定义
+
+    
+    
+    #include <stdio.h>
+    
+    #define PI 3.14159
+    #define SQUARE(x) ((x) * (x))
+    
+    int main() {
+    float radius = 2.5;
+    float area = PI * SQUARE(radius);
+    
+    printf("Area: %.2f\n", area);
+    
+    return 0;
+    }
+
+  20. 错误处理
+
+    
+    
+    #include <stdio.h>
+    #include <errno.h>
+    #include <string.h>
+    
+    int main() {
+    FILE *file = fopen("nonexistent.txt", "r");
+    if (file == NULL) {
+        printf("Error opening file: %s\n", strerror(errno));
+    } else {
+        // 文件操作
+        fclose(file);
+    }
+    
+    return 0;
+    }
+
+以上示例涵盖了C语言中的更多语法和概念，希望对你的学习有所帮助。记得不断练习和探索，以加深对C语言的理解和掌握。
+
+当然，以下是更多的C语言代码示例，涵盖了更多的语法和概念：
+
+  21. 位字段
+
+    
+    
+    #include <stdio.h>
+    
+    struct Flags {
+    unsigned int isRed : 1;
+    unsigned int isGreen : 1;
+    unsigned int isBlue : 1;
+    };
+    
+    int main() {
+    struct Flags f;
+    f.isRed = 1;
+    f.isGreen = 0;
+    f.isBlue = 1;
+    
+    printf("Red: %u\n", f.isRed);
+    printf("Green: %u\n", f.isGreen);
+    printf("Blue: %u\n", f.isBlue);
+    
+    return 0;
+    }
+
+  22. 类型转换
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    int a = 10;
+    double b = 3.14;
+    
+    double result = (double)a + b;
+    
+    printf("Result: %.2f\n", result);
+    
+    return 0;
+    }
+
+  23. 函数参数默认值
+
+    
+    
+    #include <stdio.h>
+    
+    void greet(char *name, char *message) {
+    if (name == NULL) {
+        name = "Guest";
+    }
+    printf("Hello, %s! %s\n", name, message);
+    }
+    
+    int main() {
+    greet(NULL, "Welcome to the program.");
+    greet("John", "Nice to meet you.");
+    
+    return 0;
+    }
+
+  24. 结构体指针与箭头操作符
+
+    
+    
+    #include <stdio.h>
+    #include <stdlib.h>
+    
+    typedef struct {
+    int x;
+    int y;
+    } Point;
+    
+    int main() {
+    Point *p = (Point *)malloc(sizeof(Point));
+    p->x = 2;
+    p->y = 3;
+    
+    printf("x: %d\n", p->x);
+    printf("y: %d\n", p->y);
+    
+    free(p);
+    
+    return 0;
+    }
+
+  25. 逗号运算符
+
+    
+    
+    #include <stdio.h>
+    
+    int main() {
+    int a = 2, b = 3, c = 4, result;
+    
+    result = (a * b) + (c - a), a++, b++, c++;
+    
+    printf("Result: %d\n", result);
+    printf("a: %d\n", a);
+    printf("b: %d\n", b);
+    printf("c: %d\n", c);
+    
+    return 0;
+    }
+
+以上示例涵盖了C语言中的更多语法和概念，希望对你的学习有所帮助。记得不断练习和探索，以加深对C语言的理解和掌握。