How to return 0 in this function?

[JackieCho]

double MeasureCornerAngle(int nCoord,const double coord[],int index)
{
	if (index < 1 || index > nCoord*2-2)
    {
         return 0.0;
    }
        else
    {
         do something,get a value and use the value when this function is called.
    }

}

This function must return 0.0 if the given index is smaller than 1 or greater than the number of nCoord*2-2.But I cannot write it this way,because I got a warning'Control may reach end of non-valid function'

How should I organize my code to meet the above requirement?

[InfinityCounter]

Well this can be simply solved in several ways.

the value 0.0 is the same as 0, therefore changing it to zero will still work. Like so:

double MeasureCornerAngle(int nCoord,const double coord[],int index)
{
	if (index < 1 || index > nCoord*2-2)
    {
         return 0;
    }
        else
    {
         return 1.0; //This can be any value that you choose
    }

}

you could also assign zero to a variable and return that variable instead.