After re-reading the instructions for these sets of problems, I found that I should replace multiple statements of code used for one action with a method().
Additionally, the best practice is comment your preconditions and post conditions before every method in your program.
This practice helps in writing the code without getting off track.
It took a little while to learn that if I initialize an “Int” variable in the class before my methods, and if I use “Int” with the same variable again inside the method, then I am re-declaring the variable as a local variable, and the class variable will not retain it’s values throughout the different methods. If you want a variable’s values to be available to that variable throughout your methods, only declare the type one time in the class.
A few “firsts” for me in this app was 1. The use of the break; command to exit a loop. and 2. The use of if(){} else {if{}} and 3. Methods() to replace multiple statements.
So here is the much-cleaned up and easier to read/use (and working) solution to Problem 3:
/*
* File: FindRange.java
* Name: Jason Coltrin
* Section Leader: n/a
* --------------------
* This file is the starter file for the FindRange problem.
* write a ConsoleProgram that reads in a list of integers, one per line, until a sentinel value of 0
* is entered. When the sentinel is read, your program should display the smallest and largest values
* in the list.
* The program should handle the following special cases:
* • If the user enters only one value before the sentinel, the program should report
* that value as both the largest and smallest.
* • If the user enters the sentinel on the very first input line, then no values have been
* entered, and your program should display a message to that effect.
*/
import acm.program.*;
public class FindRange extends ConsoleProgram {
int num1; // declare num1 as int
int num2; // declare num2 as int
int getNum = 1; // declare getNum as int and give initial value of 1. Later,
// if getNum = 0, then it will break the getuntilzero loop
int highNum; // declare the largest number as int
int lowNum; // declare the lowest number as int
public void run() {
// Print game description
println("This program finds the largest and smallest numbers.");
/*
* Precondition is high/low variables are initialized as int.Post
* condition is if getNum1 = 0 then message "Please try again.". If
* number is not = 0, set both highNum and lowNum to getNum1
*/
getNum1();
/*
* Precondition is highNum == lowNum. Get a new number, num2, and if
* num2 = 0 then print "Highest: highNum" and "Lowest: lowNum" and end
* the method/program. If num2 is not = 0 determine if num2 is greater
* than highNum or less than lowNum. If num2 > highNum, highNum is now
* equal to num2. If num2 < lowNum, then lowNum is now equal num2. If
* num2 is equal to highNum and num2 is equal to lowNum, then getNum2
* again. Postcondition is num2 is now set to set to either lowNum or
* highNum. lowNum is the lower number. highNum is the higher number.
* lowNum is not equal to highNum.
*/
getNum2();
/*
* Precondition is lowNum is not equal to highNum. get a new number
* getNum. while getNum is not equal to 0, if getNum < lowNum, then
* lowNum is now equal to getNum. if getNum is higher than highNum, then
* highNum is now equal to highNum. get a new number again. if getNum is
* equal to zero, display the highest and lowest numbers and end the
* method/program Postcondition is largest and smallest numbers are
* displayed.
*/
getUntilZero();
}
public void getNum1() {
num1 = readInt("?:");
if (num1 == 0) {
println("Please try again without 0.");
getNum1();
}
highNum = num1;
lowNum = num1;
}
public void getNum2() {
if ((highNum != 0) && (lowNum != 0)) {
num2 = readInt("?:");
if (num2 == 0) {
println("Biggest number:" + highNum);
println("Smallest number:" + lowNum);
getUntilZero();
} else {
if (num2 > highNum) {
highNum = num2;
} else {
if (num2 < lowNum) {
lowNum = num2;
} else {
if ((num2 == highNum) && (num2 == lowNum))
getNum2();
}
}
}
}
}
public void getUntilZero() {
while ((getNum != 0) && (highNum != lowNum)) {
getNum = readInt("?:");
if (getNum == 0) {
displayHighLow();
endApp();
break;
} else {
if (getNum < lowNum) {
lowNum = getNum;
} else {
if (getNum > highNum)
highNum = getNum;
}
}
}
}
// precondition is sentinel has been entered
// postcondition is smallest and largest numbers are displayed
private void displayHighLow() {
println("Smallest:" + lowNum);
println("Largest:" + highNum);
}
// :-)
private void endApp() {
println("Thanks for playing");
}
}
And here is the output:
