Simple Hello Server/Client program

Server-Client Program/Server/Server.cpp

@@ -0,0 +1,86 @@
+//Server side Program in C/C++
+
+#include <stdint.h>
+#include <netinet/ip.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <errno.h>
+#include <arpa/inet.h>
+
+
+static void msg( const char* msg){
+    fprintf(stderr, "%s\n", msg);
+}
+
+static void die(const char* msg){
+    int err = errno;
+    fprintf(stderr, "[%d] %s\n", err,msg);
+    abort();
+}
+
+static void do_something(int connfd){
+    char rbuf[64] = {};
+
+    ssize_t n = read(connfd, rbuf, sizeof(rbuf) - 1);
+
+    if( n < 0 ){
+        msg("read() error");
+        return;
+    }
+
+    printf("Client says: %s\n",rbuf);
+
+    char wbuf[] = "world";
+    write(connfd , wbuf, strlen(wbuf));
+}
+
+
+int main(){
+    //syscall to return integer for socket communication from kernel
+    int fd = socket(AF_INET, SOCK_STREAM , 0);
+    if( fd < 0 ){
+        die("socket()");
+    }
+
+    //Set the option in various layer which will establish communication.
+    int val = 1;
+    setsockopt(fd, SOL_SOCKET , SO_REUSEADDR, &val , sizeof(val));
+
+    //bind, dealing wih IPv4 addresses
+    struct sockaddr_in addr = {};
+    addr.sin_family = AF_INET;
+    addr.sin_port = ntohs(1234);
+    addr.sin_addr.s_addr = ntohl(0);// wildcard address 0.0.0.0
+    int rv = bind(fd, (const sockaddr*)&addr, sizeof(addr));
+
+    if(rv){
+        die("bind()");
+    }
+
+    //listen
+    rv = listen(fd , SOMAXCONN);
+
+    if( rv ){
+        die("listen()");
+    }
+
+    //Looping to connect to each connection.
+    while(true){
+        //accept
+        struct sockaddr_in client_addr = {};
+        socklen_t socklen = sizeof( client_addr );
+        int connfd = accept(fd , (struct sockaddr*)& client_addr, &socklen);
+        if( connfd < 0 ){
+            //error
+            printf("Error encountered while connecting with client.");
+        }
+
+        do_something(connfd);
+        close(connfd);
+    }
+
+    return 0;
+}