using for loop in mathematica.

Questions
1

hi i want use for loop in mathematica but i do not know what is the role of i++? i think this loop is equal to
for i=1:4
print(i)
end
in matlab. Do I understand correctly?
For[i = 0, i < 4, i++, Print[i]]

2

i++ increments i by 1 each time.

increment documentation

This is the same as For[i = 0, i < 4, i=i+1, Print[i]]

For[i = 0, i < 4, i=i+1/4, Print[i]] increments i by 1/4 each time, similar to Matlab for i=1:1/4:4 print(i) end

3

See my comment to your other question:

http://community.wolfram.com/groups/-/m/t/395069