How do I input this?

Specific Example:

im inputting the following into a character array:

42.5 + 7 - 3 =

i want to separare the float and char from the char array into two separate stacks and also stop at the = sign.

General Example:

The expression above can change as it is inputted by the user. If anyone has any better way of inputting such an expression so that its parts go into two different arrays (one char and one float) and stops at the = please let me know how to do it....I have been working on this for a week and and it is the only part of my program that does not work. I appreciate all your help greatly.

Thanks - Rob

Oh and BTW for many of those who have given me examples of how to do this in the past week (thanks), I need something far less complex as I am just a beginning programmer.

Thanks again - Rob