I'm trying to add 100 to each elements of the list using a for loop

I saved the desired values (from the list 100)to a variable a; then replace each element of the list using the index and the variable a;

List<Integer> numbers= new ArrayList<>();
        numbers.add(8);
        numbers.add(9);
        numbers.add(22);
        numbers.add(42);
        numbers.add(100);

for(int i=0;i<numbers.size();i  ){
            int a=numbers.get(i) 100;
            numbers.add(i,a);
       }

        System.out.println("The new elements of the list are "  numbers);

CodePudding user response：

According to the Javadoc for java.util.List, numbers.add(i,a) inserts a at index i. You should use numbers.set(i, a) instead since you don't want to insert new elements but replace existing ones.

CodePudding user response：

numbers.add(i,a) don't replace the element at position i. It inserts a new element at that position, thus increasing the size of the numbers array. Use the method numbers.set(i,a) instead