AC vs DC currents advantage disadvantage

When supplying current to premises over a wide area there is always a voltage drop due to line resistance. AC can be stepped-up quite simply, using a transformer. At higher voltages, the current is lower and the resistive losses are less - so overhead power lines use many thousands of volts which can then be stepped-down to the normal voltage(s) used. One disadvantage of AC is that all power stations must be synchronised before connecting to the grid to ensure the sine waves are all the same frequency and phase.

DC voltage cannot be changed easily, especially at high currents but has the advantage that lighting will not have any "flicker" and audio amplifiers would not have any mains hum.

In terms of safety, I don't think there is much difference between them - if the voltages are equal and high enough, they both hurt!

Depends what you want it for, but most electronic stuff runs off DC, and those that run off AC could be manufactured to run off DC in most cases. The main advantage of AC is that it is more economical to transport. Due to inevitable losses in running long distance cables, electricity needs to be supplied at a much higher voltage than what we receive in our homes. It will be run to a local sub station or sometimes even when it arrives at the house, where it will be dropped down to the right voltage.
In the case of AC this is easily accomplished through transformers, whereas DC cannot go through a transformer, and would need a resistive load to drop it's voltage. This would mean huge heat losses.

Ac is far safer
Ac can transmit further
Except underwater, when electrons are lost every time direction changes, here dc is better
Dc is easier to produce (batteries)
Ac is usually better, because of safety, but often dc is the only choice