"function" was not declared in this scope (called in setup)

Question

I have this bit of code I'm trying to execute only once. but I seem to get this error every time I try to compile: "calcOppervlakte' was not declared in this scope" when it's being called in the setup.

I've looked at code examples where calling functions like this works, and I cannot wrap my head around this problem.

google isn't really helpful either since the search for something-something not declared in this scope gets me thousands of results.

double pi = 3.14159265359;
void setup() {
 Serial.begin(9600);
 for(int r = 1; r <11; r++){
 Serial.print(calcOppervlakte(r)); <----
 }
}
void loop() { 
}
double calcOpppervlakte(float radius){
 double result = pi * pow(radius, 2);
 return result;
}

Answer 1

The function name you're calling is calcOppervlakte but the function name in the definition is calcOpppervlakte. If you look closely you'll see there is an extra p in the function definition. If you change the names to match the error will be resolved.