1. 计算器程序
一个简单的计算器程序可以帮助你理解C语言的基本语法和控制结构。以下是一个基本的计算器程序示例:
#include <stdio.h>
int main() {
char operator;
double firstNumber, secondNumber;
printf("Enter an operator (+, -, *, /): ");
scanf("%c", &operator);
printf("Enter two operands: ");
scanf("%lf %lf", &firstNumber, &secondNumber);
switch (operator) {
case '+':
printf("%.1lf + %.1lf = %.1lf", firstNumber, secondNumber, firstNumber + secondNumber);
break;
case '-':
printf("%.1lf - %.1lf = %.1lf", firstNumber, secondNumber, firstNumber - secondNumber);
break;
case '*':
printf("%.1lf * %.1lf = %.1lf", firstNumber, secondNumber, firstNumber * secondNumber);
break;
case '/':
if (secondNumber != 0.0)
printf("%.1lf / %.1lf = %.1lf", firstNumber, secondNumber, firstNumber / secondNumber);
else
printf("Division by zero is not allowed.");
break;
default:
printf("Error! operator is not correct");
}
return 0;
}
2. 字符串处理
使用C语言处理字符串,例如实现字符串反转:
#include <stdio.h>
#include <string.h>
void reverseString(char str[]) {
int len = strlen(str);
int i;
char temp;
for (i = 0; i < len / 2; i++) {
temp = str[i];
str[i] = str[len - i - 1];
str[len - i - 1] = temp;
}
}
int main() {
char str[] = "Hello, World!";
printf("Original String: %s\n", str);
reverseString(str);
printf("Reversed String: %s\n", str);
return 0;
}
3. 队列实现
学习如何使用C语言实现队列数据结构:
#include <stdio.h>
#include <stdlib.h>
#define MAX 100
int queue[MAX];
int front = -1;
int rear = -1;
void enqueue(int item) {
if (rear == MAX - 1) {
printf("Queue is full\n");
} else {
if (front == -1) {
front = 0;
}
rear++;
queue[rear] = item;
}
}
int dequeue() {
int item;
if (front == -1) {
printf("Queue is empty\n");
return -1;
} else {
item = queue[front];
if (front == rear) {
front = -1;
rear = -1;
} else {
front++;
}
return item;
}
}
int main() {
enqueue(1);
enqueue(2);
enqueue(3);
printf("%d dequeued from queue\n", dequeue());
printf("%d dequeued from queue\n", dequeue());
return 0;
}
4. 函数递归
递归函数是一个重要的概念,以下是一个使用递归计算阶乘的示例:
#include <stdio.h>
long factorial(int n) {
if (n == 0)
return 1;
else
return n * factorial(n - 1);
}
int main() {
int number;
printf("Enter a positive integer: ");
scanf("%d", &number);
printf("Factorial of %d = %ld\n", number, factorial(number));
return 0;
}
5. 排序算法
实现一个排序算法,如冒泡排序,来理解C语言中的循环和比较逻辑:
#include <stdio.h>
void bubbleSort(int arr[], int n) {
int i, j, temp;
for (i = 0; i < n-1; i++) {
for (j = 0; j < n-i-1; j++) {
if (arr[j] > arr[j+1]) {
temp = arr[j];
arr[j] = arr[j+1];
arr[j+1] = temp;
}
}
}
}
int main() {
int arr[] = {64, 34, 25, 12, 22, 11, 90};
int n = sizeof(arr)/sizeof(arr[0]);
bubbleSort(arr, n);
printf("Sorted array: \n");
for (int i=0; i < n; i++)
printf("%d ", arr[i]);
printf("\n");
return 0;
}
6. 链表操作
使用C语言实现链表数据结构,并进行插入和删除操作:
#include <stdio.h>
#include <stdlib.h>
struct Node {
int data;
struct Node* next;
};
void push(struct Node** head_ref, int new_data) {
struct Node* new_node = (struct Node*) malloc(sizeof(struct Node));
new_node->data = new_data;
new_node->next = (*head_ref);
(*head_ref) = new_node;
}
void deleteNode(struct Node** head_ref, int key) {
struct Node *temp = *head_ref, *prev;
if (temp != NULL && temp->data == key) {
*head_ref = temp->next;
free(temp);
return;
}
while (temp != NULL && temp->data != key) {
prev = temp;
temp = temp->next;
}
if (temp == NULL) return;
prev->next = temp->next;
free(temp);
}
void printList(struct Node *node) {
while (node != NULL) {
printf("%d ", node->data);
node = node->next;
}
printf("\n");
}
int main() {
struct Node* head = NULL;
push(&head, 1);
push(&head, 3);
push(&head, 2);
printf("Created Linked list is: ");
printList(head);
deleteNode(&head, 1);
printf("Linked List after Deletion of 1: ");
printList(head);
return 0;
}
7. 文件操作
学习如何使用C语言进行文件操作,例如读取和写入文件:
#include <stdio.h>
int main() {
FILE *fp;
char ch;
fp = fopen("example.txt", "r");
if (fp == NULL) {
printf("Error opening file\n");
return 0;
}
printf("Reading characters from file:\n");
while ((ch = fgetc(fp)) != EOF) {
printf("%c", ch);
}
fclose(fp);
return 0;
}
8. 网络编程
使用C语言进行基本的网络编程,例如创建一个简单的TCP服务器:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
int main() {
int server_fd, new_socket;
struct sockaddr_in address;
int opt = 1;
int addrlen = sizeof(address);
// Creating socket file descriptor
if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
perror("socket failed");
exit(EXIT_FAILURE);
}
// Forcefully attaching socket to the port 8080
if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) {
perror("setsockopt");
exit(EXIT_FAILURE);
}
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons(8080);
// Forcefully attaching socket to the port 8080
if (bind(server_fd, (struct sockaddr *)&address, sizeof(address))<0) {
perror("bind failed");
exit(EXIT_FAILURE);
}
if (listen(server_fd, 3) < 0) {
perror("listen");
exit(EXIT_FAILURE);
}
while ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen))) {
printf("Connection accepted\n");
char buffer[1024] = {0};
read(new_socket, buffer, 1024);
send(new_socket, "Hello from server", 18, 0);
close(new_socket);
}
if (new_socket < 0) {
perror("accept");
exit(EXIT_FAILURE);
}
return 0;
}
9. 图形用户界面编程
使用C语言结合GTK库进行图形用户界面编程:
#include <gtk/gtk.h>
static void activate(GtkApplication* app, gpointer user_data) {
GtkWidget *window;
window = gtk_application_window_new(app);
gtk_window_set_title(GTK_WINDOW(window), "GTK Application");
gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
gtk_container_set_border_width(GTK_CONTAINER(window), 10);
GtkWidget *label = gtk_label_new("Hello, GTK!");
gtk_window_set_child(GTK_WINDOW(window), label);
gtk_widget_show(window);
}
int main(int argc, char **argv) {
GtkApplication *app;
int status;
app = gtk_application_new("org.gtk.example", G_APPLICATION_FLAGS_NONE);
g_signal_connect(app, "activate", G_CALLBACK(activate), NULL);
status = g_application_run(G_APPLICATION(app), argc, argv);
g_object_unref(app);
return status;
}
10. 数据库连接
使用C语言连接Oracle数据库,执行SQL语句:
”`c
#include
int main() {
OCIEnv *envhp;
OCIServer *srvhp;
OCISession *seshp;
OCISessionPool *sesp;
OCIError *errhp;
ub4 n = 0;
ub4 r = 0;
ub4 nattr = 0;
ub4 rattr = 0;
ub4 column;
ub4 row;
ub4 colcount = 0;
ub4 rowcount = 0;
ub4 size = 0;
ub4 colsize = 0;
ub4 rowsize = 0;
ub4 len = 0;
ub4 type = 0;
ub4 len2 = 0;
ub4 type2 = 0;
ub4 len3 = 0;
ub4 type3 = 0;
ub4 len4 = 0;
ub4 type4 = 0;
ub4 len5 = 0;
ub4 type5 = 0;
ub4 len6 = 0;
ub4 type6 = 0;
ub4 len7 = 0;
ub4 type7 = 0;
ub4 len8 = 0;
ub4 type8 = 0;
ub4 len9 = 0;
ub4 type9 = 0;
ub4 len10 = 0;
ub4 type10 = 0;
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ub4 type11 = 0;
ub4 len12 = 0;
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ub4 len14 = 0;
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ub4 type15 = 0;
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ub4 type16 = 0;
ub4 len17 = 0;
ub4 type17 = 0;
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ub4 len20 = 0;
ub4 type20 = 0;
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ub4 type21 = 0;
ub4 len22 = 0;
ub4 type22 = 0;
ub4 len23 = 0;
ub4 type23 = 0;
ub4 len24 = 0;
ub4 type24 = 0;
ub4 len25 = 0;
ub4 type25 = 0;
ub4 len26 = 0;
ub4 type26 = 0;
ub4 len27 = 0;
ub4 type27 = 0;
ub4 len28 = 0;
ub4 type28 = 0;
ub4 len29 = 0;
ub4 type29 = 0;
ub4 len30 = 0;
ub4 type30 = 0;
ub4 len31 = 0;
ub4 type31 = 0;
ub4 len32 = 0;
ub4 type32 = 0;
ub4 len33 = 0;
ub4 type33 = 0;
ub4 len34 = 0;
ub4 type34 = 0;
ub4 len35 = 0;
ub4 type35 = 0;
ub4 len36 = 0;
ub4 type36 = 0;
ub4 len37 = 0;
ub4 type37 = 0;
ub4 len38 = 0;
ub4 type38 = 0;
ub4 len39 = 0;
ub4 type39 = 0;
ub4 len40 = 0;
ub4 type40 = 0;
ub4 len41 = 0;
ub4 type41 = 0;
ub4 len42 = 0;
ub4 type42 = 0;
ub4 len43 = 0;
ub4 type43 = 0;
ub4 len44 = 0;
ub4 type44 = 0;
ub4 len45 = 0;
ub4 type45 = 0;
ub4 len46 = 0;
ub4 type46 = 0;
ub4 len47 = 0;
ub4 type47 = 0;
ub4 len48 = 0;
ub4 type48 = 0;
ub4 len49 = 0;
ub4 type49 = 0;
ub4 len50 = 0;
ub4 type50 = 0;
ub4 len51 = 0;
ub4 type51 = 0;
ub4 len52 = 0;
ub4 type52 = 0;
ub4 len53 = 0;
ub4 type53 = 0;
ub4 len54 = 0;
ub4 type54 = 0;
ub4 len55 = 0;
ub4 type55 = 0;
ub4 len56 = 0;
ub4 type56 = 0;
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ub4 type57 = 0;
ub4 len58 = 0;
ub4 type58 = 0;
ub4 len59 = 0;
ub4 type59 = 0;
ub4 len60 = 0;
ub4 type60 = 0;
ub4 len61 = 0;
ub4 type61 = 0;
ub4 len62 = 0;
ub4 type62 = 0;
ub4 len63 = 0;
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ub4 len64 = 0;
ub4 type64 = 0;
ub4 len65 = 0;
ub4 type65 = 0;
ub4 len66 = 0;
ub4 type66 = 0;
ub4 len67 = 0;
ub4 type67 = 0;
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ub4 type68 = 0;
ub4 len69 = 0;
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ub4 type70 = 0;
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ub4 type73 = 0;
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ub4 type74 = 0;
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ub4 type75 = 0;
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ub4 len80 = 0;
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ub4 type81 = 0;
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ub4 type86 = 0