No exit from "if"

hi everybody,
could explain me why following scketch doesn't work? stupid program 3 leds , 4.7 kohm thermistor (that 1 included in workshop kit - base level).
the problem lights red led if temperature rises 22°c (green led) 23 °c (yellow led).
serial monitor gives me correct temperature red led on!!!
maybe if cycle wrong...
attached frizing sketch!

thanks

code: [select]


#include <math.h>

const int sensorpin = 1;    
int sensorvalue;  
int led1 = 2; //green led
int led2 = 4; //yellow led
int led3 = 7; //red led
float tensione;
float rt;
float temp;

void setup() {
 pinmode (led1,output);
 pinmode (led2,output);
 pinmode (led3,output);
 serial.begin(9600);}

void loop() {
 sensorvalue = analogread(sensorpin);    
 tensione=4.83-((4.83*sensorvalue)/1024);
 rt=20000*((4.83-tensione)/tensione);
 temp = 10.5915*tensione*tensione - 55.5533*tensione + 67.3157;
 serial.print(sensorvalue);
 serial.print(" -> ");
 serial.print(tensione);
 serial.print(" -> ");
 serial.print(rt);
 serial.print(" (");
 serial.print(temp);
 serial.println(" gradi)");
 
 if(temp <= 23);
   {digitalwrite(led1, high);
    digitalwrite(led2, low);
    digitalwrite(led3, low);}
   
 if(temp > 23 && temp <= 38);
   {digitalwrite(led1, low);
    digitalwrite(led2, high);
    digitalwrite(led3, low);}
   
 if(temp > 38);
   {digitalwrite(led1, low);
    digitalwrite(led2, low);
    digitalwrite(led3, high);}
   
delay(500);
}
moderatore added code tags -> use # button above smileys,

you have never, ever seen example code "if"s written those.
examine them carefully

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