Control reach end of non-void function - objective-c

Question

Please consider following code:
-(NSString*)getNextOvulationString{
if (self.daysToNextOvulation < 0){
return [NSString stringWithFormat:#"Овуляция была %li дней назад", labs(self.daysToNextOvulation)];
} else if (self.daysToNextOvulation == 0){
return [NSString stringWithFormat:#"Овуляция началась"];
} else if (self.daysToNextOvulation > 0){
return [NSString stringWithFormat:#"Овуляция началась"];
}
}
There is 3 cases, and obvious, we will get one guaranteed.
Still, compiler not allow me to build, because of error:
Control reach end of non-void function
How to fix that?

Answer 1

Since the final condition is the exhaustive case, change the final else if to an else and call it a day. If you want, add your condition as a same-line comment to keep it clear.
The end result would be something like this:
- (NSString *)getNextOvulationString
{
if (self.daysToNextOvulation < 0)
{
return [NSString stringWithFormat:#"Овуляция была %li дней назад", labs(self.daysToNextOvulation)];
}
else if (self.daysToNextOvulation == 0)
{
return [NSString stringWithFormat:#"Овуляция началась"];
}
else // self.daysToNextOvulation > 0
{
return [NSString stringWithFormat:#"Овуляция началась"];
}
}
You could also drop the final else altogether like this:
- (NSString *)getNextOvulationString
{
if (self.daysToNextOvulation < 0)
{
return [NSString stringWithFormat:#"Овуляция была %li дней назад", labs(self.daysToNextOvulation)];
}
else if (self.daysToNextOvulation == 0)
{
return [NSString stringWithFormat:#"Овуляция началась"];
}
// self.daysToNextOvulation > 0
return [NSString stringWithFormat:#"Овуляция началась"];
}
And since the last two conditions both return the same thing you could even write it this way:
- (NSString *)getNextOvulationString
{
if (self.daysToNextOvulation < 0)
{
return [NSString stringWithFormat:#"Овуляция была %li дней назад", labs(self.daysToNextOvulation)];
}
else // self.daysToNextOvulation >= 0
{
return [NSString stringWithFormat:#"Овуляция началась"];
}
}
Or this way, again dropping the else entirely:
- (NSString *)getNextOvulationString
{
if (self.daysToNextOvulation < 0)
{
return [NSString stringWithFormat:#"Овуляция была %li дней назад", labs(self.daysToNextOvulation)];
}
// self.daysToNextOvulation >= 0
return [NSString stringWithFormat:#"Овуляция началась"];
}
Note: All of the above pieces of code are functionally equivalent given the current conditions and return values.

Answer 2

You need to add else at last to return the NSString, so change you if condition like this.
-(NSString*)getNextOvulationString{
if (self.daysToNextOvulation < 0){
return [NSString stringWithFormat:#"Овуляция была %li дней назад", labs(self.daysToNextOvulation)];
}
else if (self.daysToNextOvulation == 0){
return [NSString stringWithFormat:#"Овуляция началась"];
}
else //No need to compare here
return [NSString stringWithFormat:#"Овуляция началась"];
}
}