Java Basic - explanation of for loops

Code Java:

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class GraphPanel extends Panel
//GraphPanel is being defined as subclass of Panel
    implements Runnable, MouseListener, MouseMotionListener { //runnable
//using an interface, allows q method from ore than one superclass
    Graph graph; //attribute  or variable
    int nnodes; //attribute  or variable, primitive data type
    Node nodes[] = new Node[100];
    int nedges; //attribute  or variable intial value
    Edge edges[] = new Edge[200];
    Thread relaxer;
 
    GraphPanel(Graph graph) {
    this.graph = graph;
    addMouseListener(this);
    }
 
 
    int findNode(String lbl) {
    for (int i = 0 ; i < nnodes ; i++) {
//statement executes if  test returns true
        }
    }

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Just in regards to the for loop, not sure what the i < nnodes is testing. Is it comparing i to the individual value of each nnodes variable, or is it comparing to see whether i is less than the length of nnodes array?

nnodes is an integer variable. It's comparing i to the integer value of nnodes.

The "for" statement does 3 things. First you declare/intantiate something. Then you declare a condition. Finally, you declare an action. In your example, you create an integer 'i', check that the value of 'i' is less than the value of 'nnodes', and if so, add 1 to the value of 'i'. The loop is repeated as long as these conditions are met.

Code :

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for(int i=0; i< nnodes; i++)
{
//Put code here that you want to be executed every time the conditions of the loop are met.
}

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