Initialize variable to highest possible value?

Assume that you are looking for a minimum value in a loop, you would like to initialize the check variable to the highest possible value, in order to prevent missing a value during the minimization.

I know that this is possible in JAVA, but is there a similar value in IGOR?
If you search for the minimum/maximum of values in a wave I' suggest to use WaveStats /M=0/Q instead.
It is much faster and better readable than any handcrafted loop.
Thanks for the hints - I am comparing the slopes of adjacent data points of a spectrum by windowing, so since I compare calculated values, I have to go for a loop - (I will post the snippet here for evaluation when I finish the code)

Anyhow, I often wondered whether it would make sense not using the built-in functions (like, Interpolate or Wave_Min()) too much for learning purposes - and in order to make code written in IGOR portable to other IDEs and other languages...

I personally felt one of the biggest "disadvantages" of IGOR to be that it is not possible to compile stand-alone programs...
You also might want to look into using do-while loops instead of for-loops, which are much easier to run indefinitely until you break the loop with a custom condition (e.g., just use while(1)).