14.13

The

break

 Statement

BLOCKS AND STATEMENTS

class Graph {

int edges[][];

public Graph(int[][] edges) { this.edges = edges; }

public Graph loseEdges(int i, int j) {

int n = edges.length;

int[][] newedges = new int[n][];

for (int k = 0; k < n; ++k) {

edgelist: {

int z;

search: {

if (k == i) {

for (z = 0; z < edges[k].length; ++z)

if (edges[k][z] == j)

break search;

} else if (k == j) {

for (z = 0; z < edges[k].length; ++z)

if (edges[k][z] == i)

break search;

}

//

No edge to be deleted; share this list.

newedges[k] = edges[k];

break edgelist;

}//search

//

Copy the list, omitting the edge at position

z.

int m = edges[k].length   1;

int ne[] = new int[m];

System.arraycopy(edges[k], 0, ne, 0, z);

System.arraycopy(edges[k], z+1, ne, z, m z);

newedges[k] = ne;

}//edgelist

}

return new Graph(newedges);

}

}

Note the use of two statement labels,

edgelist

 and

search

, and the use of

break

statements. This allows the code that copies a list, omitting one edge, to be shared

between two separate tests, the test for an edge from node

i

 to node

j

, and the test

for an edge from node

j

 to node

i

.

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