Converting strings to Upper case in C++

I need to make sure that the letters in a string are uppercase to do some searching in a vector. The format of the string will be "A9999", but the user needs to be able to put in "a9999" and have it find their account. I seem to remember a funtion that would make a string uppercase. if any of you know, please tell me so I can do this.
I appreciate it alot.

You can try looping through the characters in the string, using "toupper" from ctype.h (or just cctype if your not using the ".h" version)

Can't you simply use strupr() from string.h ?
It's not ANSI so maybe you wouldn't want to include it though.