double to char* conversion. Weird results from dtostrf

Here’s the code:

void setup() { Serial.begin(9600); delay(300); double lat = 1111.11; double lon = 4444.44; const byte len{10}; char sLat[len]; char sLon[len]; dtostrf(lat, len, 2, sLat); Serial.println(sLat); Serial.println("---"); dtostrf(lon, len, 2, sLon); Serial.println(sLon); Serial.println(sLat); // <-- prints nothing! Serial.println("---"); dtostrf(lat, len, 2, sLat); Serial.println(sLat); Serial.println(sLon); // <-- prints nothing! } void loop() { } 

Here’s the output:

 1111.11 --- 4444.44 --- 1111.11 4444.44 1111.11 

As you see. Every next call for dtostrf ruins the previous results, in a weird way.

What’s the problem?