Destroy on collide

Hello, I am making a game with a hero and an enemy, I want the hero to disappear when the enemy touches the hero and I want the game to restart. I am an absolute beginner. I am still learning so thanks!

@CalebAnder Are you going to use the physics engine for your objects, or are you going to calculate a collision on your own.

@CalebAnder Here’s an example using the physics engine. The enemy is dropping from the top and the hero is fixed. When the enemy hits the hero, the hero disappears and when the enemy falls off the bottom of the screen, the program restarts.

function setup()
    a1=physics.body(CIRCLE,40)
    a1.x=300
    a1.y=HEIGHT-100
    a2=physics.body(CIRCLE,40)
    a2.x=300
    a2.y=200
    a2.type=STATIC
end

function draw()
    background(40, 40, 50)
    sprite("Tyrian Remastered:Evil Head",a1.x,a1.y)
    if a2~=nil then
        sprite("Platformer Art:Guy Standing",a2.x,a2.y)
    end
    if a1.y<-50 then
        restart()
    end
end

function collide(c)
    if c.state==BEGAN then
        a2:destroy()
        a2=nil
    end
end

@CalebAnder Here’s the above example not using the physics engine.

function setup()
    show=true
    a1x=300
    a1y=HEIGHT-100
    a2x=300
    a2y=200
end

function draw()
    background(40, 40, 50)
    sprite("Tyrian Remastered:Evil Head",a1x,a1y)
    if show then
        sprite("Platformer Art:Guy Standing",a2x,a2y)
    end
    checkPosition()
end

function checkPosition()
    v1=vec2(a1x,a1y)
    d=v1:dist(vec2(a2x,a2y))
    if d<75 then
        show=false
    end  
    a1y=a1y-2
    if a1y<-50 then
        restart()
    end
end

Thanks Dave, helped a lot! I have just started using codea so I will ask for help a lot!