Control Flow Graph – How to Create a Control Flow Graph for a Function

control flowdesigngraph

Given is a short Java function and I like to create a control flow graph for it but I'm not sure if it's fine like that? Because I left some things away such as variables that have already been created with the function together (int[] A, boolean[] boo).

boolean func(int[] A, boolean[] boo){
    boolean res;
    int n, leng;
    leng = A.length;
    n = 0;
    res = true;
    while(n < leng){
        if(A[n] <= 0 && !boo[n]){
            res = false;
        }
        n++;
    }
    return res;
}

Link to the chart

Is it fine like that? Because in the test I write soon I would do it like that : /

Best Answer

Control flow graphs are usually not written with one statement per node, but divide the code into basic blocks that combine multiple statements. A basic block starts with a jump target and ends with a jump to another block. The jump at the end may be conditional.

Your control flow graph is generally correct, except

that it could be simplified by using basic blocks
that the n++ node has multiple outgoing jumps, but isn't a conditional statement. There must not be a direct jump from n++ to return res, instead there should only be the jump back to the while (...).

Related Solutions

Java Enums – Handling Multiple Boolean Properties

You can take the idea one step further and define an enum for your page features instead of using booleans.

This makes it easy to add/remove a feature to a page and makes the page definitions instantly readable even when there are 30-40 potential features.

public enum PageFeature {
    AVAIL_PAGE,
    SHOPPING_CART;
}

public enum Page {
    FOFP(AVAIL_PAGE),
    FOMS(AVAIL_PAGE),
    BKGD(),
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    private final EnumSet<PageFeature> features;

    PageCode(PageFeature ... features) {
       this.features = EnumSet.copyOf(Arrays.asList(features));
    }

    public boolean hasFeature(PageFeature feature) {
       return features.contains(feature);
    }
 }

Design Patterns – OOP Way of Handling Flow Control Heavy Applications

One approach that might fit is a finite state machine. There are tools that help you build and visualize them but you can also model it with standard OOP practices.

Best Answer

Related Solutions

Java Enums – Handling Multiple Boolean Properties

Design Patterns – OOP Way of Handling Flow Control Heavy Applications

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