What is the difference between IFRS & GAAP?

Now which GAAP you are referring to? GAAP stands for Generally Accepted Accountingn Principles. And there are many: UK, US, China Canada,etc.

IFRS are principles based (flexible in nature as it captures the economics and nature of a business transaction) while GAAP like in the US are rules based (inflexible).

The answer to this question is very vague. I hope my answer was helpful.