Capital Gain - question

#1
Just need to know that if one do not have any other source of income. do he/she still have to pay capital gain tax on shares?

I checked an online calculator which was showing 0 capital gain tax for not having any other source of income but was showing capital gain tax with other source of income.

Thanx.
 
#3
short term capital gain are chargeable @10%
and other income @slab rates
if TOtal taxable income including STCG is less then the exemtion limit then whole STCG is exepmt