Revert "Update checkpoints.cpp"

This reverts commit 138c46a63ad02e024461755408aca5ff708fd8f2.
Revert "Update main.cpp"

This reverts commit 4bf85b5f7a08858bda6d6af1c1e5345182065ac5.
Revert "Update main.cpp"

This reverts commit 52cb05e077ca5ab578ccbbffbfcf1ce413c7e1f7.