File content as of revision 0:7c734e5f2c45:

#include "mbed.h"
#include "EthernetInterface.h"
#include "PubSubClient.h"
#include "RHT03.h" 
#include <iostream>
#include <sstream>
#include <string>
#include <iomanip>

Serial pc(USBTX, USBRX);
DigitalOut myled(LED1);

char* serverIpAddr = "192.168.1.2";  
int port = 1883; 


void callback(char* topic, char* payload, unsigned int len);
PubSubClient mqtt(serverIpAddr, port, callback);
EthernetInterface  eth;

void callback(char* topic, char* payload, unsigned int len)
{
    printf("Topic: %s\r\n", topic);
    printf("Payload: %s\r\n\r\n", payload);
    
    //Send incoming payloads back to topic.
    //mqtt.publish("mbed/mybehive", payload, len);
}

int main() {

    float temp,hum;
    RHT03 humtemp(p24); 
    string var;
    
    printf("\r\nMQTTClient Tester\r\n");
    eth.init(); //Use DHCP
    eth.connect();

    printf("IP Address is %s\n\r", eth.getIPAddress());  
    
    char clientID[] = "charlie";   /*Client nanme show for MQTT server*/
    char pub_topic[] = "mbed/mybehive";   /*Publish to topic : "/mbed" */

    
    if(!mqtt.connect(clientID)){
        pc.printf("\r\nConnect to server failed ..\r\n");
        return -1;
    }
    
    printf("\r\nConnect to server sucessed ..\r\n");
      
    while(1) {
        mqtt.loop();
        myled = 1;
        wait(3);

        pc.printf("Read temperature\n\r");
        if(humtemp.readData() == RHT_ERROR_NONE) 
        {
            //Gets the current temperature in centigrade
            temp = humtemp.getTemperatureC();
            //Gets the current humidity in percentage 
            hum = humtemp.getHumidity(); 
            
            stringstream oss;
            oss << "{" << "\"temperature\":" << std::setprecision(4) << temp << "," << "\"humidity\":" << std::setprecision(4) << hum << "}";
            
            string data = oss.str();            
            pc.printf("temperature is %f\n\r", temp);
            pc.printf("humidity is %f\n\r\n\r", hum);
            pc.printf("environment is %s\n\r\n\r", data.c_str());
            char * value = new char [37];
            strcpy(value, data.c_str());
            mqtt.publish(pub_topic, value);
        }
        myled = 0;
        wait(3);
    }
}