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

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。