Indentation & Comments 8-Jul-19

Overview Indentation isn't important to the correctness of Java programs (the computer totally ignores it), but it can make a big difference to the readability of your programs. Note: In other languages, like Python, indentation is necessary

Version without indentation method main(){ Jeroo Sally = new Jeroo(); while(!Sally.isWater(AHEAD)) { Sally.hop();} Sally.turn(RIGHT); while(!Sally.isWater(AHEAD)) { Sally.hop();} Sally.turn(RIGHT); while(!Sally.isWater(AHEAD)) { Sally.hop();} Sally.turn(RIGHT); while(!Sally.isWater(AHEAD)) { Sally.hop();} Sally.turn(RIGHT);} What does it do???

with indentation the meaning is easier to see method main() {     Jeroo Sally = new Jeroo();     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT); } the meaning is easier to see

add in comments method main() {     Jeroo Sally = new Jeroo();     // Go along the top (north) edge of the island     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     // Go along the right (east) edge of the island     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     // Go along the bottom (south) edge of the island     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     // Go along the left (west) edge of the island     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     // Note that this last turn is needed to ensure that Sally is facing east     // again, as required in the problem statement.     Sally.turn(RIGHT); } now, anyone could look at the program and know exactly what it does.

Comments describe what is happening in the program method main() {     Jeroo Sally = new Jeroo();     // this is a loop     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     // this is a loop     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     // another loop     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     // still looping     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     // a turn     Sally.turn(RIGHT); } NOT stating the obvious These are lousy comments!

refining further… of course, there are areas of repeated code… perfect candidates for creating methods how would you rewrite it to be more efficient using methods? can you still create a program as readable as the example given here?

add in comments This could be a method method main() {     Jeroo Sally = new Jeroo();     // Go along the top (north) edge of the island     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     // Go along the right (east) edge of the island     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     // Go along the bottom (south) edge of the island     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     Sally.turn(RIGHT);     // Go along the left (west) edge of the island     while(!Sally.isWater(AHEAD)) {         Sally.hop();     }     // Note that this last turn is needed to ensure that Sally is facing east     // again, as required in the problem statement.     Sally.turn(RIGHT); } This could be a method Repeated code makes a good method Or would this be a better choice for a method?

The End The important point is to make a reasonable effort to communicate to your human readers as well as to the computer. Comments and indentation are the 2 tools for making a program readable, for others who may need to use your code, and for yourself later on when you may have forgotten the details of your program.