Viper - this has got to be either a wind-up or a misunderstanding.
In case it's a misunderstanding I'll describe a basic stall turn (a hammerhead in US parlance) and a wingover, you can say which your "instructor" did.
In a stall turn the aircraft is accelerated level to some reasonable speed and pulled to a true vertical attitude (upwards). It's kept vertical as the speed decays until the time is right to apply rudder to make it yaw through 180 degrees (inside its wingspan) and so retrace its path back towards terra firma, at a reasonable speed it is pulled into level flight. The actual process is more complex than this, there are several pitfalls if you don't get it right and the g probably ranges between 0 and +4.
A wingover can be flown in a number of ways but basically the aircraft is pitched to +30-60 degrees, partly unloaded and rolled smoothly to 60-90 degrees as the pitch drops to zero (climbing turn) followed by undoing what you've just done on the way back down again. These are legitimate in a C172 providing they're flown smoothly and inside the permitted g range.
Which was it? If it was the first then I suggest you fly with someone else.