Java question Write a simple calculator program that takes input from the user t
ID: 3846018 • Letter: J
Question
Java question
Write a simple calculator program that takes input from the user to perform addition, subtraction, multiplication, and division.
a)Write a method called prompt that will print to output a prompt for the user, asking whether they want to perform (a)ddition, (s)ubtraction, (m)ultiplication, or (d)ivision, or else (q)uit the calculator. Your method should not take any parameters, but should use the Scanner class to take input from the user after giving the appropriate prompt. Your method should return a character that corresponds to the first character of the String given by the user as input. If it is a letter, the returned character should be lower case.
b)Write a method called intCalculator that will perform integer arithmetic on a set of values given by the user. Your method should take a single character as a parameter that should indicate whether addition, subtraction, multiplication, or division will be performed (‘a’, ‘s’, ‘m’, or ‘d’, respectively). Your method should also print out a prompt indicating that the user should enter two integer values. Your method should not return any value, but should print out the result of performing the indicated arithmetic operation on the two values given by the user.
c)Write a main method that uses the methods from parts (a) and (b) together to perform as many integer arithmetic operations as the user desires, until they enter ‘q’ to quit. If the user enters something that does not correspond to one of the five characters indicated in the prompt (‘a’, ‘s’, ‘m’, ‘d’, or ‘q’), then the program should print another prompt, and continue printing prompts until valid input is given. For example, a single run of the program should result in something similar to the following set of output prompts and input values from the user:
Do want to (a)dd, (s)ubtract, (m)ultiply, (d)ivide, or (q)uit?
add
Enter two integer values to add:
2 5
Your result is: 7
Do want to (a)dd, (s)ubtract, (m)ultiply, (d)ivide, or (q)uit?
d
Enter two integer values to divide:
13 2
Your result is: 6
Do want to (a)dd, (s)ubtract, (m)ultiply, (d)ivide, or (q)uit?
wuit
Do want to (a)dd, (s)ubtract, (m)ultiply, (d)ivide, or (q)uit?
q
Explanation / Answer
import java.awt.*;
import java.awt.event.*;
/*********************************************/
public class MyCalculator extends Frame
{
public boolean setClear=true;
double number, memValue;
char op;
String digitButtonText[] = {"7", "8", "9", "4", "5", "6", "1", "2", "3", "0", "+/-", "." };
String operatorButtonText[] = {"/", "sqrt", "*", "%", "-", "1/X", "+", "=" };
String memoryButtonText[] = {"MC", "MR", "MS", "M+" };
String specialButtonText[] = {"Backspc", "C", "CE" };
MyDigitButton digitButton[]=new MyDigitButton[digitButtonText.length];
MyOperatorButton operatorButton[]=new MyOperatorButton[operatorButtonText.length];
MyMemoryButton memoryButton[]=new MyMemoryButton[memoryButtonText.length];
MySpecialButton specialButton[]=new MySpecialButton[specialButtonText.length];
Label displayLabel=new Label("0",Label.RIGHT);
Label memLabel=new Label(" ",Label.RIGHT);
final int FRAME_WIDTH=325,FRAME_HEIGHT=325;
final int HEIGHT=30, WIDTH=30, H_SPACE=10,V_SPACE=10;
final int TOPX=30, TOPY=50;
///////////////////////////
MyCalculator(String frameText)//constructor
{
super(frameText);
int tempX=TOPX, y=TOPY;
displayLabel.setBounds(tempX,y,240,HEIGHT);
displayLabel.setBackground(Color.BLUE);
displayLabel.setForeground(Color.WHITE);
add(displayLabel);
memLabel.setBounds(TOPX, TOPY+HEIGHT+ V_SPACE,WIDTH, HEIGHT);
add(memLabel);
// set Co-ordinates for Memory Buttons
tempX=TOPX;
y=TOPY+2*(HEIGHT+V_SPACE);
for(int i=0; i<memoryButton.length; i++)
{
memoryButton[i]=new MyMemoryButton(tempX,y,WIDTH,HEIGHT,memoryButtonText[i], this);
memoryButton[i].setForeground(Color.RED);
y+=HEIGHT+V_SPACE;
}
//set Co-ordinates for Special Buttons
tempX=TOPX+1*(WIDTH+H_SPACE); y=TOPY+1*(HEIGHT+V_SPACE);
for(int i=0;i<specialButton.length;i++)
{
specialButton[i]=new MySpecialButton(tempX,y,WIDTH*2,HEIGHT,specialButtonText[i], this);
specialButton[i].setForeground(Color.RED);
tempX=tempX+2*WIDTH+H_SPACE;
}
//set Co-ordinates for Digit Buttons
int digitX=TOPX+WIDTH+H_SPACE;
int digitY=TOPY+2*(HEIGHT+V_SPACE);
tempX=digitX; y=digitY;
for(int i=0;i<digitButton.length;i++)
{
digitButton[i]=new MyDigitButton(tempX,y,WIDTH,HEIGHT,digitButtonText[i], this);
digitButton[i].setForeground(Color.BLUE);
tempX+=WIDTH+H_SPACE;
if((i+1)%3==0){tempX=digitX; y+=HEIGHT+V_SPACE;}
}
//set Co-ordinates for Operator Buttons
int opsX=digitX+2*(WIDTH+H_SPACE)+H_SPACE;
int opsY=digitY;
tempX=opsX; y=opsY;
for(int i=0;i<operatorButton.length;i++)
{
tempX+=WIDTH+H_SPACE;
operatorButton[i]=new MyOperatorButton(tempX,y,WIDTH,HEIGHT,operatorButtonText[i], this);
operatorButton[i].setForeground(Color.RED);
if((i+1)%2==0){tempX=opsX; y+=HEIGHT+V_SPACE;}
}
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent ev)
{System.exit(0);}
});
setLayout(null);
setSize(FRAME_WIDTH,FRAME_HEIGHT);
setVisible(true);
}
//////////////////////////////////
static String getFormattedText(double temp)
{
String resText=""+temp;
if(resText.lastIndexOf(".0")>0)
resText=resText.substring(0,resText.length()-2);
return resText;
}
////////////////////////////////////////
public static void main(String []args)
{
new MyCalculator("Calculator - JavaTpoint");
}
}
/*******************************************/
class MyDigitButton extends Button implements ActionListener
{
MyCalculator cl;
//////////////////////////////////////////
MyDigitButton(int x,int y, int width,int height,String cap, MyCalculator clc)
{
super(cap);
setBounds(x,y,width,height);
this.cl=clc;
this.cl.add(this);
addActionListener(this);
}
////////////////////////////////////////////////
static boolean isInString(String s, char ch)
{
for(int i=0; i<s.length();i++) if(s.charAt(i)==ch) return true;
return false;
}
/////////////////////////////////////////////////
public void actionPerformed(ActionEvent ev)
{
String tempText=((MyDigitButton)ev.getSource()).getLabel();
if(tempText.equals("."))
{
if(cl.setClear)
{cl.displayLabel.setText("0.");cl.setClear=false;}
else if(!isInString(cl.displayLabel.getText(),'.'))
cl.displayLabel.setText(cl.displayLabel.getText()+".");
return;
}
int index=0;
try{
index=Integer.parseInt(tempText);
}catch(NumberFormatException e){return;}
if (index==0 && cl.displayLabel.getText().equals("0")) return;
if(cl.setClear)
{cl.displayLabel.setText(""+index);cl.setClear=false;}
else
cl.displayLabel.setText(cl.displayLabel.getText()+index);
}//actionPerformed
}//class defination
/********************************************/
class MyOperatorButton extends Button implements ActionListener
{
MyCalculator cl;
MyOperatorButton(int x,int y, int width,int height,String cap, MyCalculator clc)
{
super(cap);
setBounds(x,y,width,height);
this.cl=clc;
this.cl.add(this);
addActionListener(this);
}
///////////////////////
public void actionPerformed(ActionEvent ev)
{
String opText=((MyOperatorButton)ev.getSource()).getLabel();
cl.setClear=true;
double temp=Double.parseDouble(cl.displayLabel.getText());
if(opText.equals("1/x"))
{
try
{double tempd=1/(double)temp;
cl.displayLabel.setText(MyCalculator.getFormattedText(tempd));}
catch(ArithmeticException excp)
{cl.displayLabel.setText("Divide by 0.");}
return;
}
if(opText.equals("sqrt"))
{
try
{double tempd=Math.sqrt(temp);
cl.displayLabel.setText(MyCalculator.getFormattedText(tempd));}
catch(ArithmeticException excp)
{cl.displayLabel.setText("Divide by 0.");}
return;
}
if(!opText.equals("="))
{
cl.number=temp;
cl.op=opText.charAt(0);
return;
}
// process = button pressed
switch(cl.op)
{
case '+':
temp+=cl.number;break;
case '-':
temp=cl.number-temp;break;
case '*':
temp*=cl.number;break;
case '%':
try{temp=cl.number%temp;}
catch(ArithmeticException excp)
{cl.displayLabel.setText("Divide by 0."); return;}
break;
case '/':
try{temp=cl.number/temp;}
catch(ArithmeticException excp)
{cl.displayLabel.setText("Divide by 0."); return;}
break;
}//switch
cl.displayLabel.setText(MyCalculator.getFormattedText(temp));
//cl.number=temp;
}//actionPerformed
}//class
/****************************************/
class MyMemoryButton extends Button implements ActionListener
{
MyCalculator cl;
/////////////////////////////////
MyMemoryButton(int x,int y, int width,int height,String cap, MyCalculator clc)
{
super(cap);
setBounds(x,y,width,height);
this.cl=clc;
this.cl.add(this);
addActionListener(this);
}
////////////////////////////////////////////////
public void actionPerformed(ActionEvent ev)
{
char memop=((MyMemoryButton)ev.getSource()).getLabel().charAt(1);
cl.setClear=true;
double temp=Double.parseDouble(cl.displayLabel.getText());
switch(memop)
{
case 'C':
cl.memLabel.setText(" ");cl.memValue=0.0;break;
case 'R':
cl.displayLabel.setText(MyCalculator.getFormattedText(cl.memValue));break;
case 'S':
cl.memValue=0.0;
case '+':
cl.memValue+=Double.parseDouble(cl.displayLabel.getText());
if(cl.displayLabel.getText().equals("0") || cl.displayLabel.getText().equals("0.0") )
cl.memLabel.setText(" ");
else
cl.memLabel.setText("M");
break;
}//switch
}//actionPerformed
}//class
/*****************************************/
class MySpecialButton extends Button implements ActionListener
{
MyCalculator cl;
MySpecialButton(int x,int y, int width,int height,String cap, MyCalculator clc)
{
super(cap);
setBounds(x,y,width,height);
this.cl=clc;
this.cl.add(this);
addActionListener(this);
}
//////////////////////
static String backSpace(String s)
{
String Res="";
for(int i=0; i<s.length()-1; i++) Res+=s.charAt(i);
return Res;
}
//////////////////////////////////////////////////////////
public void actionPerformed(ActionEvent ev)
{
String opText=((MySpecialButton)ev.getSource()).getLabel();
//check for backspace button
if(opText.equals("Backspc"))
{
String tempText=backSpace(cl.displayLabel.getText());
if(tempText.equals(""))
cl.displayLabel.setText("0");
else
cl.displayLabel.setText(tempText);
return;
}
//check for "C" button i.e. Reset
if(opText.equals("C"))
{
cl.number=0.0; cl.op=' '; cl.memValue=0.0;
cl.memLabel.setText(" ");
}
//it must be CE button pressed
cl.displayLabel.setText("0");cl.setClear=true;
}//actionPerformed
}//class
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