I have coded a project of mine in C on a Windows machine in the software
IAR Embedded Workbench IDE
I use the ARM, AVR32 and MSP430 processor versions of the IAR toolchain. In each of these you have to implement your own low level functionality to handle the stdin and stdout streams. The ARM compiler manual has a section on "Standard streams for input and output" which says that you need to write your own version of the __write() function, and it provides an example version where the data is written to a memory mapped LED display.
Knowing IAR I would expect they will have a similar example for your processor/toolchain combination.