Check the gas supply into the home to ensure it hasn't been interrupted. The clicking sound you hear in the range is the electronic ignitor trying to light the pilot light. Inspect the gas meter to determine if it has stopped spinning or check other gas appliances in the home to ensure they're working. Call your utility company as a last resort to ask whether gas has been shut off to your home.
Test the stove-top burners to determine if they're working if there is not a problem with the home's gas supply. If the burners don't work, check the gas shutoff valve that's located behind the range to determine if it was accidentally shut off. If the shutoff valve is on, but the burners aren't working, you may have to replace the range's gas regulator, which requires a call to a technician.
Unplug the gas range's electrical cord from the outlet if the burners work and the oven doesn't. This will allow you to bypass the electronic ignitor and attempt to light the oven manually.
Remove the oven racks and unfasten the screws that secure the oven floor plate to the bottom of the range. Use a Phillips screwdriver to turn the screws counterclockwise and lift off the floor plate once they have all been removed. Turn the oven's thermostat control knob to the highest setting and hold a long barbecue lighter to the pilot light. If it lights, the electronic ignitor has malfunctioned and must be replaced. If it doesn't light, you may have a more serious problem with the range itself that requires the expertise of an appliance service technician.