Cocos2d problem/question - iphone

Question

I am making a game in Cocos2d. I want enemies to spawn on the right and left sides of the screen, and move to a random point on the screen, then repeat. Despite my efforts, I cannot figure it out. This should be relatively easy to answer, it should look like something out of one of Ray Wenderlich's tutorials. Some code would be nice. Thanks!

Answer 1

This is the code from ray Wanderlich tutorial..
[self schedule:#selector(addTarget) interval:2.0];
-(void)addTarget {
CCSprite *target = [CCSprite spriteWithFile:#"Target.jpg"
rect:CGRectMake(0, 0, 27, 40)]; //Creating Sprite and setting rect
// Determine where to spawn the target along the Y axis
CGSize winSize = [[CCDirector sharedDirector] winSize]; //Get the screensize
int minY = target.contentSize.height/2;
int maxY = winSize.height - target.contentSize.height/2;
int rangeY = maxY - minY;
int actualY = (arc4random() % rangeY) + minY;
// Create the target slightly off-screen along the right edge,
// and along a random position along the Y axis as calculated above
target.position = ccp(winSize.width + (target.contentSize.width/2), actualY);
[self addChild:target];
// Determine speed of the target
int minDuration = 2.0;
int maxDuration = 4.0;
int rangeDuration = maxDuration - minDuration;
int actualDuration = (arc4random() % rangeDuration) + minDuration;
// Create the actions
id actionMove = [CCMoveTo actionWithDuration:actualDuration
position:ccp(-target.contentSize.width/2, actualY)];
id actionMoveDone = [CCCallFuncN actionWithTarget:self
selector:#selector(spriteMoveFinished:)];
[target runAction:[CCSequence actions:actionMove, actionMoveDone, nil]];
}
minY-->position at the bottom of the screen
maxY--->position at the top of the screen.
rangeY ---> the height of the screen.
actualY--->calculate the random point between bottom of the screen and top of the screen.
target.position --> setting random position for the sprite to move.
actualDuration --> getting random duration.so that the sprite moves in various time delay.
actionMove --> creating Move action.
actionMoveDone ---> After completing move action,calling spriteMoveFinished to remove sprites.