Best way to do calculator style digit entry

Programming Questions

Elijah Bo..

Best way to do calculator style digit entry

in Programming Questions • 2 months ago

I'm working on my first project in Processing which is a calculator. I've reached a speed bump. The way I thought I could do digit entry isn't working. Anybody got any ideas?

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NOTE:

Calculator entry is like this:

*Click 7 button*

Screen reads:7

*Click 2 button*

Screen reads:72

If It helps my code is:

Calculator.pde

PFont f;
import java.math.*;
//All of the below values allow me to quickly change values code wide
final int topRowYPos = 80;
final int secondRowYPos = 110;
final int thirdRowYPos = 140;
final int fourthRowYPos = 170;
final int fithRowYPos = 200;
final int sixthRowYPos = 230;
final int buttonWidth = 35;
final int buttonHeight = 25;
final int firstRowXPos = 45;
final int secondRowXPos = 85;
final int thirdRowXPos = 125;
final int fourthRowXPos = 165;
final int fithRowXPos = 205;
final int maxB = 27;
boolean wTillUpToRefresh; //Selectes wheather you will refresh automaticly or only on next button push
int digitCount = 0; //Counts digits. Required in the process of adding digits.
PFont sF = createFont("Georgia", 16, true); //Creates font used calculator wide
boolean isDecimal; //Checks wheather I've pressed the decimal buttons. Determines wheather the number needs to be to number*10^1 or number*10^-1
double numOneBuffer = 0; //Stores firstnumber;
double numTwoBuffer = 0; //Stores second number;
int numOn = 1; //Counts which position in the calculating process the user is in. 1 is first number, 2 is function(not needed but there) 3 is second number 4 is answer mode
String functionBuffer = "N"; //Stores which function the calculation is using
String screenBuffer = "0"; //Stores what is currently being displayed on the screen
double answerBuffer = 0; //Stores answer
double numMemory = 0; //Stores one varible in "Memory"
int buttonPressed = -1; //Detects what button has been pressed
boolean sign = true;
Button[] buttons = new Button [maxB]; //Button array for all buttons
void setup() {
size(250, 280);
//The following lines initilize the buttons
buttons[0] = new Button(firstRowXPos, secondRowYPos, "MC", false);
buttons[1] = new Button(firstRowXPos, thirdRowYPos, "%", false);
buttons[2] = new Button(firstRowXPos, fourthRowYPos, "+/-", false);
buttons[3] = new Button(firstRowXPos, fithRowYPos, "C", false);
buttons[4] = new Button(firstRowXPos, sixthRowYPos, "AC", false);
buttons[5] = new Button(secondRowXPos, secondRowYPos, "MR", false);
buttons[6] = new Button(secondRowXPos, thirdRowYPos, "7", false);
buttons[7] = new Button(secondRowXPos, fourthRowYPos, "4", false);
buttons[8] = new Button(secondRowXPos, fithRowYPos, "1", false);
buttons[9] = new Button(secondRowXPos, sixthRowYPos, "0", false);
buttons[10] = new Button(thirdRowXPos, secondRowYPos, "M-", false);
buttons[11] = new Button(thirdRowXPos, thirdRowYPos, "8", false);
buttons[12] = new Button(thirdRowXPos, fourthRowYPos, "5", false);
buttons[13] = new Button(thirdRowXPos, fithRowYPos, "2", false);
buttons[14] = new Button(thirdRowXPos, sixthRowYPos, "=", false);
buttons[15] = new Button(fourthRowXPos, topRowYPos, "√", false);
buttons[16] = new Button(fourthRowXPos, secondRowYPos, "M+", false);
buttons[17] = new Button(fourthRowXPos, thirdRowYPos, "9", false);
buttons[18] = new Button(fourthRowXPos, fourthRowYPos, "6", false);
buttons[19] = new Button(fourthRowXPos, fithRowYPos, "3", false);
buttons[20] = new Button(fourthRowXPos, sixthRowYPos, ".", false);
buttons[21] = new Button(fithRowXPos, topRowYPos, "off", false);
buttons[22] = new Button(fithRowXPos, secondRowYPos, "÷", false);
buttons[23] = new Button(fithRowXPos, thirdRowYPos, "*", false);
buttons[24] = new Button(fithRowXPos, fourthRowYPos, "-", false);
buttons[25] = new Button(fithRowXPos, fithRowYPos, "", true);
buttons[26] = new Button(fithRowXPos, sixthRowYPos, "", true);
}
void draw() {
rectMode(CENTER);
fill(255);
//Calculatorbody
rect(125, 140, 240, 270);
//"Screen"
rect(125, 40, 220, 30);
//Double button
rect(fithRowXPos, 215, buttonWidth, 55, 7);
fill(0);
textAlign(CENTER);
textFont(sF, 16);
//text for double button
text("+", fithRowXPos, 215);
//updates and displays screenBuffer
update();
//displays buttons
for (int i = 0; i < maxB; i++) {
buttons[i].display();
}
}
void mousePressed() {
//Checks which button has been pressed
wTillUpToRefresh = false;
for (int i = 0; i < maxB; i++) {
if (buttons[i].isOverButton()) {
buttonPressed = i;
break;
}
}
println(buttonPressed);//Debug code
if (buttonPressed == 0) {
//Clears "Memory" if MC button is pressed
numMemory = 0;
buttonPressed = -1;
}
else if (buttonPressed == 1 && numOn != 1 && numOn != 2) {
//Takes specified percent from numOneBuffer and sets numTwoBuffer to it
numTwoBuffer = numOneBuffer*(numTwoBuffer/100);
buttonPressed = -1;
}
else if (buttonPressed == 2) {
//Sets sign of the number the "calculator" is on based on current sign and number;
if (sign && numOn == 1) {
numOneBuffer = numOneBuffer + (-2*numOneBuffer);
sign = false;
}
else if (!sign && numOn == 1) {
numOneBuffer = numOneBuffer + (-2*numOneBuffer);
sign = true;
}
else if (sign && numOn == 3) {
numTwoBuffer = numTwoBuffer + (-2*numTwoBuffer);
sign = false;
}
else if (!sign && numOn == 3) {
numTwoBuffer = numTwoBuffer + (-2*numTwoBuffer);
sign = true;
}
buttonPressed = -1;
}
else if (buttonPressed == 3) {
//Clears current number and the properties of that number
if (numOn == 1) {
numOneBuffer = 0;
isDecimal = false;
sign = true;
digitCount = 0;
answerBuffer = 0;
}
else if (numOn == 3) {
numTwoBuffer = 0;
isDecimal = false;
sign = true;
digitCount = 0;
answerBuffer = 0;
}
else if (numOn == 4) {
numOn = 1;
answerBuffer = 0;
}
buttonPressed = -1;
}
else if (buttonPressed == 4) {
//resets buffers and all numbers properties
numOneBuffer = 0;
numTwoBuffer = 0;
isDecimal = false;
digitCount = 0;
answerBuffer = 0;
screenBuffer = "";
numOn = 1;
sign = true;
buttonPressed = -1;
}
else if (buttonPressed == 5) {
//displays value in memory until next button is pressed
screenBuffer = String.valueOf(numMemory);
wTillUpToRefresh = true;
update();
buttonPressed = -1;
}
else if (buttonPressed == 6) {
//Enters the digit 7
buttonPressed = -1;
}
}
double evaluate() {
//insert code
return 1;
}
void update() {
if (!wTillUpToRefresh) {
if (numOn == 1) {
//writes numOneBuffer to screen if the user is on step one
screenBuffer = String.valueOf(numOneBuffer);
}
else if (numOn == 3) {
//writes numTwoBuffer to screen if the user is on step two
screenBuffer = String.valueOf(numTwoBuffer);
}
}
text(screenBuffer, 125, 40);
}

button.pde:

class Button {
static final int BTN_DX = 35, BTN_DY = 25; // diameters x, y
static final int BTN_RX = BTN_DX >> 1; // radius x
static final int BTN_RY = BTN_DY >> 1; // radius
final int left, right, top, bottom, centerX, centerY; // button edges and Center Coords
final String text;
final boolean isDouble;
Button (int cx, int cy, String buttonText, boolean doubleButton) {
left = cx - BTN_RX;
right = cx + BTN_RX;
top = cy - BTN_RY;
bottom = cy + BTN_RY;
centerX = cx;
centerY = cy;
text = buttonText;
isDouble = doubleButton;
}
boolean isOverButton() {
return mouseX > left & mouseX < right
& mouseY > top & mouseY < bottom;
}
void display() {
if (!isDouble) {
PFont f = createFont("Georgia", 16, true);
textFont(f, 16);
textAlign(CENTER);
fill(255);
rect(centerX, centerY, BTN_DX, BTN_DY, 7);
fill(0);
text(text, centerX, centerY + 5);
}
}
}

Any other general suggestions are welcome.

Replies(2)

PhiLho

Re: Best way to do calculator style digit entry

2 months ago

General suggestion: don't call createFont() on display(), it is a rather costly operation. Make a global PFont variable, initialize it in setup() and use it here.

About the cascading tests on numOn, see also the switch keyword.

I haven't tried your code and I find the logic a bit convoluted. I fail to understand (from a quick glance) what numOn is, and why. I don't understand where the numbers are entered.

Somehow, you can have a number corresponding to the currently displayed value. When you enter a new digit, multiply this number by 10 and add the new number. Better make this number an int (or a long), and use another int / long for the decimal part, to keep precision and avoid rounding errors.

Elijah Bo..

Re: Best way to do calculator style digit entry

2 months ago

NumOns purpose is to keep track of what number you are entering. Your suggestion is valid and I did think about doing it, but the only problem is, with the decimal hunk of the number and the main part of the number in separate hunks how do you do operations correctly. If you add them together into a double you lose all the precision you might have gained.

Thanks once again.

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