hi i need explanation why stack contains garbage while we refer to stack default is any method to clean the stack my program exit so that my stack should contain zero as default ...............................
You are not being very clear here. From the sound of your post only I will point out that if you declare a variable without initialising it, it will be given a garbage value. If you want the variable to default to zero, then initialise it zero.
If you are going to explain the problem further, please do so with some code that you have written so others can understand better your problem.