Just get data once

I'm making a thermometer using MAX6675 and the thermocouple.
I'm using Arduino Uno to get the information from the sensor when display on 3 cathode displays with multiplexing.
The problem is that it only displays the value it got right before the loading on arduino, and the same stays unless I press the reset button.
My intetion is about reading the temperature while display the value read.

Hope you guys can help to solve it ;D

Code:

/*
Temperature Reading from a MAX6675

Ryan McLaughlin ryanjmclaughlin@gmail.com
*/
#define A 8
#define B 2
#define C 3
#define D 4
#define E 5
#define f 6
#define G 7
#define WD A3
#define GND1 A2
#define GND2 A1
#define GND3 A0
#define SO 12 // MISO
#define SCK 13 // Serial Clock
#define TC_0 11 // CS Pin of MAX6607

unsigned int data=0;

int TC_0_calib = 0; // Calibration compensation value in digital counts (.25[ch730]C)

void setup() {

pinMode(A, OUTPUT);
pinMode(B, OUTPUT);
pinMode(C, OUTPUT);
pinMode(D, OUTPUT);
pinMode(E, OUTPUT);
pinMode(f, OUTPUT);
pinMode(G, OUTPUT);

pinMode(GND1, OUTPUT);
pinMode(GND2, OUTPUT);
pinMode(GND3, OUTPUT);

pinMode(WD, OUTPUT);

pinMode(SO, INPUT);
pinMode(SCK, OUTPUT);
pinMode(TC_0, OUTPUT);
digitalWrite(TC_0,HIGH); // Disable device

Serial.begin(9600);
}

void digit0 () {
// for 0 needed to turn ON F A B C D E segments, so:

digitalWrite(A, HIGH);
digitalWrite(B, HIGH);
digitalWrite(C, HIGH);
digitalWrite(D, HIGH);
digitalWrite(E, HIGH);
digitalWrite(f, HIGH);

//////////////////////// G segment should be turn OFF
digitalWrite(G, LOW);

};

void digit1 () {

digitalWrite(A,LOW);
digitalWrite(B, HIGH);
digitalWrite(C, HIGH);
digitalWrite(D, LOW);
digitalWrite(E, LOW);
digitalWrite(f, LOW);
digitalWrite(G, LOW);
};

void digit2 () {

digitalWrite(A,HIGH);
digitalWrite(B, HIGH);
digitalWrite(C, LOW);
digitalWrite(D, HIGH);
digitalWrite(E, HIGH);
digitalWrite(f, LOW);
digitalWrite(G, HIGH);
};

void digit3 () {

digitalWrite(A,HIGH);
digitalWrite(B, HIGH);
digitalWrite(C, HIGH);
digitalWrite(D, HIGH);
digitalWrite(E, LOW);
digitalWrite(f, LOW);
digitalWrite(G, HIGH);
};

void digit4 () {

digitalWrite(A,LOW);
digitalWrite(B, HIGH);
digitalWrite(C, HIGH);
digitalWrite(D, LOW);
digitalWrite(E, LOW);
digitalWrite(f, HIGH);
digitalWrite(G, HIGH);
};

void digit5 () {

digitalWrite(A,HIGH);
digitalWrite(B, LOW);
digitalWrite(C, HIGH);
digitalWrite(D, HIGH);
digitalWrite(E, LOW);
digitalWrite(f, HIGH);
digitalWrite(G, HIGH);
};

void digit6 () {

digitalWrite(A,HIGH);
digitalWrite(B, LOW);
digitalWrite(C, HIGH);
digitalWrite(D, HIGH);
digitalWrite(E, HIGH);
digitalWrite(f, HIGH);
digitalWrite(G, HIGH);
};

void digit7 () {

digitalWrite(A,HIGH);
digitalWrite(B, HIGH);
digitalWrite(C, HIGH);
digitalWrite(D, LOW);
digitalWrite(E, LOW);
digitalWrite(f, LOW);
digitalWrite(G, LOW);
};

void digit8 () {

digitalWrite(A, HIGH);
digitalWrite(B, HIGH);
digitalWrite(C, HIGH);
digitalWrite(D, HIGH);
digitalWrite(E, HIGH);
digitalWrite(f, HIGH);
digitalWrite(G, HIGH);

};

void digit9 () {

digitalWrite(A, HIGH);
digitalWrite(B, HIGH);
digitalWrite(C, HIGH);
digitalWrite(D, HIGH);
digitalWrite(E, LOW);
digitalWrite(f, HIGH);
digitalWrite(G, HIGH);

};

void showdigit (int digit)

{

switch (digit) {

case 0:
digit0 ();
break;

case 1:
digit1 ();
break;

case 2:
digit2 ();
break;

case 3:
digit3 ();
break;

case 4:
digit4 ();
break;

case 5:
digit5 ();
break;

case 6:
digit6 ();
break;

case 7:
digit7 ();
break;

case 8:
digit8 ();
break;

case 9:
digit9 ();
break;

default:

break;

};

};

void showdigits (int number)
{

// e.g. we have "1234"
int aux=0, a=0;
showdigit(number/100); // segments are set to display "1"
digitalWrite(GND1, LOW); // first digit on,
digitalWrite(GND2, LOW); // other off
digitalWrite(GND3, HIGH);

delay (4);

aux = (number%100)/10; // remainder of 1234/1000 is 234
digitalWrite(GND3, LOW); // first digit is off
showdigit(aux); //// segments are set to display "2"
digitalWrite(GND2, HIGH); // second digit is on
delay (4); // and so on....

digitalWrite(GND2, LOW);
showdigit(number%10);

digitalWrite(GND1, HIGH);
delay (4);

};

/* Create a function read_temp that returns an unsigned int
with the temp from the specified pin (if multiple MAX6675). The
function will return 9999 if the TC is open.

Usage: read_temp(int pin, int type, int error)
pin: the CS pin of the MAX6675
type: 0 for [ch730]F, 1 for [ch730]C
error: error compensation in digital counts
samples: number of measurement samples (max:10)
*/
unsigned int read_temp(int pin, int type, int error, int samples) {
unsigned int value = 0;
int error_tc;
float temp;
unsigned int temp_out;

for (int i=samples; i>0; i--){
digitalWrite(pin,LOW); // Enable device

/* Cycle the clock for dummy bit 15 */
digitalWrite(SCK,HIGH);
digitalWrite(SCK,LOW);

/* Read bits 14-3 from MAX6675 for the Temp
Loop for each bit reading the value and
storing the final value in 'temp'
*/
for (int i=11; i>=0; i--){
digitalWrite(SCK,HIGH); // Set Clock to HIGH
value += digitalRead(SO) << i; // Read data and add it to our variable
digitalWrite(SCK,LOW); // Set Clock to LOW
}

/* Read the TC Input inp to check for TC Errors */
digitalWrite(SCK,HIGH); // Set Clock to HIGH
error_tc = digitalRead(SO); // Read data
digitalWrite(SCK,LOW); // Set Clock to LOW

digitalWrite(pin, HIGH); //Disable Device
}

value = value/samples; // Divide the value by the number of samples to get the average

/*
Keep in mind that the temp that was just read is on the digital scale
from 0[ch730]C to 1023.75[ch730]C at a resolution of 2^12. We now need to convert
to an actual readable temperature (this drove me nuts until I figured
this out!). Now multiply by 0.25. I tried to avoid float math but
it is tough to do a good conversion to [ch730]F. THe final value is converted
to an int and returned at x10 power.

*/

value = value + error; // Insert the calibration error value

//if(type == 0) { // Request temp in [ch730]F
// temp = ((value0.25) * (9.0/5.0)) + 32.0; // Convert value to [ch730]F (ensure proper floats!)
// } else if(type == 1) { // Request temp in [ch730]C
temp = (value
0.25); // Multiply the value by 25 to get temp in [ch730]C
//}

temp_out = temp; // Send the float to an int (X10) for ease of printing.

/* Output 9999 if there is a TC error, otherwise return 'temp' */
if(error_tc != 0) { return 9999; } else { return temp_out; }
}

void loop()
{

read_temp(TC_0,1,TC_0_calib,10);
data = read_temp(TC_0,1,TC_0_calib,10);
//Serial.println(data);
showdigits(data);

}

Use code tags when posting code
Instead of for loops, use an index variable that you increment every pass through loop(). The for loops stop everything until completed. loop() does just what it says.