Remove first item from Array in Javax

Question

Got an assignment question which asks to return the first item from an array and then remove it. If the array is empty I should return null. Here is my code:

public String pop(){
    if(arrayLength == 0){
        return null;
    }else{
        String[] temp = new String[100];
        String firstItem = StringStack[0];
        for(int i = 1; i<StringStack.length; i++){
            temp[i] = StringStack[i];
        }
        StringStack = temp;
        return firstItem;
    }
}

The arrayLength variable is set by this method and works fine:

public int getLength(){
    int count = 0;
    for (String s : StringStack) {
        if (s != null) {
            count++;
        }
    }
    return count;
}

I cant figure out what it is I am doing wrong here. Another part of this question is I cant use any collections or Systems.arraycopy so I have to use for loops and other basic operators to solve this. It also has to be an array so I cant use array lists or other data structures.

Answer 1

here is version with two fixed problems:

public String pop() {
    if(StringStack == null || StringStack.length == 0)
        return null;

    String firstItem = StringStack[0];

    String[] temp = new String[StringStack.length-1]; // allocate proper size
    for(int i = 1; i<StringStack.length; i++){
        temp[i-1] = StringStack[i]; // i-1 for temp array
    }
    StringStack = temp;

    return firstItem;
}

Answer 2

Got an assignment question which asks to return the first item from an array and then remove it. If the array is empty I should return null. Here is my code:

public String pop(){
    if(arrayLength == 0){
        return null;
    }else{
        String[] temp = new String[100];
        String firstItem = StringStack[0];
        for(int i = 1; i<StringStack.length; i++){
            temp[i] = StringStack[i];
        }
        StringStack = temp;
        return firstItem;
    }
}

The arrayLength variable is set by this method and works fine:

public int getLength(){
    int count = 0;
    for (String s : StringStack) {
        if (s != null) {
            count++;
        }
    }
    return count;
}

I cant figure out what it is I am doing wrong here. Another part of this question is I cant use any collections or Systems.arraycopy so I have to use for loops and other basic operators to solve this. It also has to be an array so I cant use array lists or other data structures.