twitter library and char msg[]

Hi, I am very new to the Arduino scene. I am currently working to get my Arduino to tweet. I have my ethernet shield and twitter library up and i can successfully tweet when a button is pressed. However I cannot seem to get my arduino to accept anything other than a string for char msg[]

when i try to put char msg[] = "hello" + "goodbye", i get
error: invalid operands of types 'const char [6]' and 'const char [8]' to binary 'operator+

when i try and tweet a random number, char msg[] = "hello" + random(100), i get
error: initializer fails to determine size of 'msg'

Why cant i use anything other than a single string for my tweeted message?

Here is my code, and thanks for your help!

#include <Ethernet.h>
#include <EthernetDHCP.h>
#include <EthernetDNS.h>
#include <Twitter.h>

const int buttonPin = 2;
int buttonState = 0;



byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 130, 65, 114, 80 };
byte gateway[] = { 130, 65, 114, 254 };
byte subnet[] = { 255, 255, 255, 0 };

// Your Token to Tweet
Twitter twitter("my token");

// Message to post
char msg[ ] = "hellogoodbye";

void setup()
{
  
  pinMode(buttonPin, INPUT);
  
  delay(1000);
  Ethernet.begin(mac, ip, gateway, subnet);
  Serial.begin(9600);
  
  Serial.println("I am connecting ...");

 
  
}

void loop(){
  

  buttonState = digitalRead(buttonPin);
  
  if (buttonState == HIGH) {
       Serial.println("button pressed"); 
       if (twitter.post(msg)) {
    int status = twitter.wait();
    if (status == 200) {
      Serial.println("Tweeted!");
    } else {
      Serial.print("failed : code ");
      Serial.println(status);
    }
  } else {
    Serial.println("connection failed.");
  }
  
  } 
  else {
     
  }
  
}

when i try to put char msg[] = "hello" + "goodbye",

You can't add string pointers.

Have a look at "strcat".

BTWchar msg[] = "hello" "goodbye";
is perfectly valid C.

Thanks but i'm looking to tweet something other than a string. Perhaps some numbers from an analog input like a potentiometer or something. It wont allow me to put anything besides a "string"

make the numbers into a string: itoa