error using floatToString

Using Arduino Programming Questions
#1

I trying to display temperature and humidity on a LCD48

84 module. the temperature reading function returns a float, the lcd module expects a string. The floatToString function returns the result as char * name. My code is thus:

[code]#include "LCD4884.h"
#include "DFrobot_bmp.h"
#include <SHT1x.h>

#define dataPin  10   // DATA
#define clockPin 11   // SCK
SHT1x sht1x(dataPin, clockPin);

 #include "floatToString.h"  //set to whatever is the location of floatToStrig



// menu starting points

#define MENU_X	10		// 0-83
#define MENU_Y	1		// 0-5


int  adc_key_val[5] ={50, 200, 400, 600, 800 };




void setup(){
  lcd.LCD_init();
  lcd.LCD_clear();
  Serial.begin(9600); 
}
/* loop */

void loop()
{
  float temp_f;
  float humidity;


  // Read values from the sensor
  char tempString[25]; // just give it plenty to write out any values you want to test
  temp_f = sht1x.readTemperatureF();
  Serial.println("floatToString(tempString, temp_f , 4);");
  tempString += " F"
  lcd.LCD_write_string_big(15,1,tempString,MENU_NORMAL);*/

  humidity = sht1x.readHumidity();
//  lcd.LCD_write_string_big(15,1,
}

The error I get is:

TEMP_HUM_LCD.cpp: In function ‘void loop()’:
TEMP_HUM_LCD:40: error: invalid operands of types ‘char [25]’ and ‘const char [3]’ to binary ‘operator+’
TEMP_HUM_LCD:40: error: in evaluation of ‘operator+=(char [25], const char [3])’
TEMP_HUM_LCD:41: error: expected `;’ before ‘lcd’
TEMP_HUM_LCD:41: error: expected primary-expression before ‘/’ token

I’m still a newbie, unsure of where to go from here!

Jim[/code]

#2

The compiler has certain rules about how to write your code, and it is not forgiving about random letters here and there.

Both of these lines have syntax problems. 

  lcd.LCD_write_string_big(15,1,tempString,MENU_NORMAL);*/

This has an extra */ on the end

  tempString += " F"

This is missing a semi-colon at the end.

And it is also completely not legal at all. You cannot do math (e.g. +=) on char arrays.

#3

Thanks maniacbug, I have a problem with the ;'s because Quickbasic(the only language I sort know) does not require them. I commented out the other line and it compiles without error. Now I'll work on inserting the "F".

Jim

#4