GAAP and AASB are the names of two different accounting bodies that help companies to handle all the operations relating to accounting and to help them create comprehensive financial statements. GAAP is used mostly in the United States of America to help companies prepare their financial statements by using various accounting standards and guidelines.
AASB is the short form of the Australian Accounting Standards Board. From its full form, it is an accounting body based in Australia. It provides a lot of services similar to GAAP, but its standards and guidelines are structured according to the existing laws in Australia.
GAAP and AASB mostly provide comparative financial statements, but a single period financial statement is allowed in GAAP. Both don't follow a specific layout when creating financial statements, but public companies are usually advised to use S-X regulations and requirements if they are using GAAP, whereas this is not a must if you're using AASB.