Request for member 'ping_median' in 'sonar', which is of non-class type 'NewPing [3]'

[shanren]

Hi,
a question about NewPing again, the example of NewPing3Sensors_ls from NewPing defined NewPing sonar[SONAR_NUM] and NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); in NewPingTimerMedian_M.
How can I use them the way below?
Please let me know If need I'll upload the examples.
Thanks
Adam

// ---------------------------------------------------------------------------
// Example NewPing library sketch that pings 3 sensors 20 times a second.
// ---------------------------------------------------------------------------

#include <NewPing.h>

#define SONAR_NUM 3      // Number of sensors.
#define MAX_DISTANCE 200 // Maximum distance (in cm) to ping.

NewPing sonar[SONAR_NUM] = {   // Sensor object array.
  NewPing(4, 5, MAX_DISTANCE), // Each sensor's trigger pin, echo pin, and max distance to ping. 
  NewPing(6, 7, MAX_DISTANCE), 
  NewPing(8, 9, MAX_DISTANCE)
};

float duration, distance;

void setup() {
  Serial.begin(115200); // Open serial monitor at 115200 baud to see ping results.
}

void loop() { 
  for (uint8_t i = 0; i < SONAR_NUM; i++) { // Loop through each sensor and display results.
    
    delay(50); // Wait 50ms between pings (about 20 pings/sec). 29ms should be the shortest delay between pings.
    Serial.print(i);
    Serial.print("=");
    Serial.print(sonar[i].ping_cm());
    Serial.print("cm ");
  }
  Serial.println();
  duration = sonar.ping_median(iterations);
  
}

ERROR:

Arduino: 1.8.3 (Windows 7), Board: "Arduino/Genuino Uno"

C:\Users\HUA.DELLV-PC\Documents\Arduino\NewPing3Sensors_ls\NewPing3Sensors_ls.ino: In function 'void loop()':

NewPing3Sensors_ls:32: error: request for member 'ping_median' in 'sonar', which is of non-class type 'NewPing [3]'

   duration = sonar.ping_median(iterations);

                    ^

NewPing3Sensors_ls:32: error: 'iterations' was not declared in this scope

   duration = sonar.ping_median(iterations);

                                ^

exit status 1
request for member 'ping_median' in 'sonar', which is of non-class type 'NewPing [3]'

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

[anon73444976]

@shanren

  duration = sonar.ping_median(iterations)

For which element of the array sonar did you intend the operation?

[shanren]

Thanks.
I modified as:

void loop() { 
  for (uint8_t i = 0; i < SONAR_NUM; i++) { // Loop through each sensor and display results.
    
    delay(50); // Wait 50ms between pings (about 20 pings/sec). 29ms should be the shortest delay between pings.
    Serial.print(i);
    Serial.print("=");
    Serial.print(sonar[i].ping_cm());
    Serial.print("cm ");

    duration[i] = sonar.ping_median(iterations);
  }
  Serial.println();
  ///// duration[i] = sonar.ping_median(iterations);
  
}

still got error:

Arduino: 1.8.3 (Windows 7), Board: "Arduino/Genuino Uno"

C:\Users\HUA.DELLV-PC\Documents\Arduino\NewPing3Sensors_ls\NewPing3Sensors_ls.ino: In function 'void loop()':

NewPing3Sensors_ls:34: error: request for member 'ping_median' in 'sonar', which is of non-class type 'NewPing [3]'

     duration[i] = sonar.ping_median(iterations);

                         ^

NewPing3Sensors_ls:34: error: 'iterations' was not declared in this scope

     duration[i] = sonar.ping_median(iterations);

                                     ^

exit status 1
request for member 'ping_median' in 'sonar', which is of non-class type 'NewPing [3]'

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

I guess the ping_median need : NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // NewPing setup of pins and maximum distance.
I just don't want to use like trig1/trig2...,
any easy way?

[anon73444976]

@shanren

sonar.ping_median(iterations)

sonar is an array.
Arrays need subscripts.

[shanren]

Great!!!
Works now, thank you.
Edit and see if got some clue?
The code run well, but the results is not right, why?