Loading...
More C Posts
// Client side implementation of UDP client-server model#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <arpa/inet.h>#include <netinet/in.h>#define PORT 8008#define MAXLINE 1024// Driver codeint main() {char buffer[MAXLINE];struct sockaddr_in servaddr;// Creating socket file descriptorint sockfd = socket(AF_INET, SOCK_DGRAM, 0);if ( sockfd < 0 ) {perror("socket creation failed");exit(EXIT_FAILURE);}struct timeval timeout;timeout.tv_sec = 1; //Wait 1 secondtimeout.tv_usec = 0;if (setsockopt (sockfd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof timeout) < 0) perror("setsockopt failed\n");if (setsockopt (sockfd, SOL_SOCKET, SO_SNDTIMEO, &timeout, sizeof timeout) < 0) perror("setsockopt failed\n");memset(&servaddr, 0, sizeof(servaddr));// Filling server informationservaddr.sin_family = AF_INET;servaddr.sin_port = htons(PORT);servaddr.sin_addr.s_addr = inet_addr("192.168.4.65");for(int i = 0; i < 10; ++i){char* message = "PING";int sendStatus = sendto(sockfd, (const char *)message, strlen(message), MSG_CONFIRM, (const struct sockaddr *) &servaddr, sizeof(servaddr));if(sendStatus >= 0){printf("Sent PING\n");}else{printf("Send failed\n");continue;}int len = sizeof(struct sockaddr_in);int bytesRecieved = recvfrom(sockfd, (char *)buffer, MAXLINE, MSG_WAITALL, (struct sockaddr *) &servaddr, &len); //We can reuse servaddr because the port the server sends messages from is the same one we send toif(bytesRecieved >= 0){buffer[bytesRecieved] = '\0';printf("Recieved %s\n", buffer);}else{printf("Recieved nothing: Packet Dropped\n", buffer);}}close(sockfd);return 0;}
#include <stdio.h>#include <stdlib.h>// give an array of identical coins (ints), represented by 1's and one 2// we can find the heavy coin (2) by summing the contents of the thirdsint sum_subarr(int arr[], int l, int r){int sum = 0;for(int i = l; i <= r; i++){sum += arr[i];}return sum;}int heavy_coin(int arr[], int l, int r){if(r == l){return r;}int midl = l + (r - l)/3;int midr = r - (r - l)/3;int lw = sum_subarr(arr, l, midl);int mw = sum_subarr(arr, midl + 1, midr);if ( lw > mw ){return heavy_coin(arr, l, midl);}else if ( lw < mw ){return heavy_coin(arr, midl + 1, midr);}else{return heavy_coin(arr, midr + 1, r);}}int main(int argc, char *argv[]){int arr[] = {1,1,1,1,2,1,1,1,1};int l = 0;int r = 8;int res = -1;res = heavy_coin(arr, l, r);printf("Hevy coin is at index: %d\n", res);return EXIT_SUCCESS;}
// The following code is the fast inverse square root implementation from Quake III Arena// this code has been stripped of C preprocessor directives, but includes the exact original comment textfloat Q_rsqrt( float number ){long i;float x2, y;const float threehalfs = 1.5F;x2 = number * 0.5F;y = number;i = * ( long * ) &y; // evil floating point bit level hackingi = 0x5f3759df - ( i >> 1 ); // what the fuck?y = * ( float * ) &i;y = y * ( threehalfs - ( x2 * y * y ) ); // 1st iteration// y = y * ( threehalfs - ( x2 * y * y ) ); // 2nd iteration, this can be removedreturn y;}
// compile: gcc socketTCPClient.c -o socketTCPClient.out// usage : ./socketTCPClient.out port// Doesn't send anything, just connects and prints out the response from the server#include <sys/socket.h>#include <sys/types.h>#include <netinet/in.h>#include <netdb.h>#include <stdio.h>#include <string.h>#include <stdlib.h>#include <unistd.h>#include <errno.h>#include <arpa/inet.h>int main(int argc, char *argv[]){int sockfd = 0, n = 0, portno;char recvBuff[1025];struct sockaddr_in serv_addr;memset(recvBuff, '0', sizeof(recvBuff));if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){printf("socket error\n");exit(EXIT_FAILURE);}serv_addr.sin_family = AF_INET;portno = atoi(argv[1]);serv_addr.sin_port = htons(portno);serv_addr.sin_addr.s_addr = inet_addr("127.0.0.1");if(connect(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0){printf("connect error\n");exit(EXIT_FAILURE);}while((n = read(sockfd, recvBuff, sizeof(recvBuff)-1)) > 0){recvBuff[n] = 0;if (fputs(recvBuff, stdout) == EOF){printf("fputs error\n");}}if(n < 0){printf("read error\n");}return 0;}
// Server side implementation of UDP client-server model#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <arpa/inet.h>#include <netinet/in.h>#define PORT 8008#define RECIEVE_BUFFER_SIZE 1024const char* responseMessage = "Hello from server";// Driver codeint main() {//Create a UDP socket//int socket(int domain, int type, int protocol);//Domain is the place where the data goes. AF_BLUETOOTH, AF_INET6, AF_UNIX is local communication between different programs//Type is the type of connection, so connection based (TCP), connectionless (UDP) or somewhere in between or beyond//Protocol is an enum or flags that give some more options specific to that type. For SOCK_STREAM, you can force it to use SCTP instead of TCP. For SOCK_RAW, it can give you control over the ip frame, and even the ethernet frame.//So this function makes a file descriptor to an IPV4 UDP 'connection' with no options.int sockfd = socket(AF_INET, SOCK_DGRAM, 0);// Creating socket file descriptorif ( sockfd < 0) {perror("socket creation failed");exit(EXIT_FAILURE);}struct sockaddr_in serverAddress;memset(&serverAddress, 0, sizeof(serverAddress));// Filling server informationserverAddress.sin_family = AF_INET; // IPv4serverAddress.sin_addr.s_addr = INADDR_ANY;serverAddress.sin_port = htons(PORT);// Bind the socket with the server addressif(bind(sockfd, (const struct sockaddr*)&serverAddress, sizeof(serverAddress))){ //Bind returns 0 if succeeded, or -1 if failed. -1 is still true.perror("bind failed");exit(EXIT_FAILURE);}struct sockaddr_in clientAddress; unsigned int clientAddressSize = sizeof(clientAddress);memset(&clientAddress, 0, clientAddressSize);char buffer[RECIEVE_BUFFER_SIZE];int bytesRecieved = recvfrom(sockfd, (char*)buffer, RECIEVE_BUFFER_SIZE, MSG_WAITALL, (struct sockaddr*) &clientAddress, &clientAddressSize); //sets clientAddress to the client's address and the new sizebuffer[bytesRecieved] = '\0';printf("Client : %s\n", buffer);sendto(sockfd, (const char*)responseMessage, strlen(responseMessage), MSG_CONFIRM, (const struct sockaddr*) &clientAddress, clientAddressSize);printf("Hello message sent.\n");return 0;}
#include <stdio.h>#include <stdlib.h>calculate(a, b)int a;int b;{printf("%d", a+b);}main(argc, argv)int argc;char** argv;{if(argc < 3){return 0;}calculate(atoi(argv[1]), atoi(argv[2]));}