How to use two Sonar's I'm using a single sonar, but I want to use two sonar to know another distance.

Here is how I use my single sonar:

    #include &lt;NewPing.h&gt;

    #define TRIGGER_PIN  9
    #define ECHO_PIN  10
    #define MAX_DISTANCE  100 // in CM
    ...
    NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); 
    ...
    delay(100); 
    unsigned int uS = sonar.ping(); 
    int cm = uS / US_ROUNDTRIP_CM; 


But I Want to use a second one to calculate another distance, how to?

#define TRIGGER_PIN_2  11
#define ECHO_PIN_2  12
...
new NewPing sonar(TRIGGER_PIN_2, ECHO_PIN_2, MAX_DISTANCE);
...
???


Thanks in advance

EDIT:

Maybe this one, I'll try this when I will get my second sonar

#define SONAR_NUM     2
#define MAX_DISTANCE 200
...
NewPing sonar[SONAR_NUM] = {     
  NewPing(9, 10, MAX_DISTANCE),
  NewPing(11, 12, MAX_DISTANCE)
};
...
delay(100); 
unsigned int uS1 = sonar[0].ping(); 
int cm1 = uS1 / US_ROUNDTRIP_CM; 

unsigned int uS2 = sonar[1].ping(); 
int cm2 = uS2 / US_ROUNDTRIP_CM;
Maybe this one, I'll try this when I will get my second sonar


Ding ding ding! Yeah, this would be one way to do that. That creates an array so you can reference the sonar with sonar[i], where i is either 0 or 1 for the first or second number.

For only two sensors, it might be easier just to do something like this:

NewPing sonar1(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);
NewPing sonar2(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);


Then you can run the other code like this:

delay(100); 
unsigned int uS1 = sonar1.ping(); 
int cm1 = uS1 / US_ROUNDTRIP_CM; 

unsigned int uS2 = sonar2.ping(); 
int cm2 = uS2 / US_ROUNDTRIP_CM;


A little less code to read, whichever one you want.

The reason you can do this is you can replace the sonar with whatever you wanted (following C++ variable rules like no spaces, etc.). You could call it Arduino_Sonar if you wanted to. 

The array is basically a simple way of grouping variables together easily. It's not convenient to declare 500 differently name variables; I can just do int numbers[500]; to declare them. An array might be more useful if you're expanding your circuit, but either is correct.