How to limit distance a character can travel per turn

I am building a turn-based game that involves having the option to move around the map, I only want to allow each character to move so far per turn. How would i allow the character to go only so far then force him to stop?

This only really answerable as a high-level design question, as showing you exactly how to make the system would likely take hours.

The absolute simplest way would be to give your characters some kind of ‘movement speed’ stat that defined how far they could move in a single turn. If you were using spaces on a grid, this would be how many spaces they could travel before their turn automatically ended. A character with a “Speed” of 5, could say, move back and forth 5 spaces, or north 5 spaces. You could just as easily calculate this not using spaces, but simply as a measure of distance from where you started. Remember: End Point - Starting Point = Distance.

The far more complicated solution would be to preview how far on the map the player could walk at a maximum distance, IE Fire Emblem or Shining Force.

For both of these scenarios, you will likely need input and UI to allow the player to skip remainder of the character’s movement turn and stay still.