Litecoin has specified that their maximum supply will be four times that of Bitcoin. Therefore, if Bitcoin limit is 21 million then Litecoin limit is going to be 84 million. So where does this difference come from, if GetBlockSubsidy function in Litecoin & Bitcoin is the same as shown below.
Suggestion: Litecoin team need to update the comments in their code.
The difference lies in the value of consensusParams.nSubsidyHalvingInterval, which can be found in the chainparams.cpp file for both the coins as shown in the code snippet below. For Bitcoin, the halving happens at block # 210000 and for Litecoin, it happens at block #840000.
With a little help from excel, you can work out maximum supply of Litecoin when reward approaches to zero as shown below.
