Receiving a sms from a specific number - c++

Question

I am working on a project where my Arduino ATMEGA328 interfaced in SIM900 GSM Shield will receive an sms from the specific number.
I was able to receive the message. But I want my GSM to only receive from a specific number. For example, i only want to receive from [phone] number only. Numbers like [phone] and [phone] and other will be discarded. Can anyone can help me?
EDIT: This is my code.
#include <SoftwareSerial.h>
#include <string.h>
char inchar; // Will hold the incoming character from the GSM shield
String s = "";
SoftwareSerial SIM900(2, 3);
void setup()
{
Serial.begin(9600);
// wake up the GSM shield
SIM900power();
SIM900.begin(9600);
delay(20000); // give time to log on to network.
SIM900.print("AT+CMGF=1\r"); // set SMS mode to text
delay(100);
SIM900.print("AT+CNMI=2,2,0,0,0\r");
// blurt out contents of new SMS upon receipt to the GSM shield's serial out
delay(100);
Serial.println("Ready...");
}
void SIM900power()
// software equivalent of pressing the GSM shield "power" button
{
digitalWrite(9, HIGH);
delay(1000);
digitalWrite(9, LOW);
delay(7000);
}
void loop()
{
if(SIM900.available() > 0)
{
if(SIM900.find("[phone] ") && SIM900.find("AUTO"))
{
Serial.println("AUTOMATIC asd");
SIM900.println("AT+CMGD=1,4");
}
}
}

Answer 1

I was able to receive the message. But I want my GSM to only receive
from a specific number.
Do you wish to stop the GSM from receiving SMS from unknown numbers, or do you want to output to serial when the conditions are met?
If it's the former, you may want to talk to your network provider, and consider the architectures pitfalls in this approach.
It immediately deletes the message once it does not satisfies the
condition
On that same if condition where you discard the sms if not sent from numXXX,
add an
else{
SIM900.print("AT+CNMI=2,2,0,0,0\r");
Serial.println("AUTOMATIC asd");
SIM900.println("AT+CMGD=1,4");
// or write high to led pin if that's what you want.......
}
Of course, it would help if we could see that sketch...