Calculator

Main_Activity.java

package com.example.calcultors;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

Button but_Add, but_Sub, but_Mul, but_Div;
EditText txt_Num1, txt_Num2;
TextView txt_Res;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

txt_Num1 = (EditText) findViewById(R.id.Num1);
txt_Num2 = (EditText) findViewById(R.id.Num2);
txt_Res = (TextView) findViewById(R.id.TV);

but_Add = (Button) findViewById(R.id.ADD);
but_Sub = (Button) findViewById(R.id.SUB);
but_Mul = (Button) findViewById(R.id.MUL);
but_Div = (Button) findViewById(R.id.Div);

but_Add.setOnClickListener(this);
but_Sub.setOnClickListener(this);
but_Mul.setOnClickListener(this);
but_Div.setOnClickListener(this);
}


@Override
public void onClick(View v) {
double Op1=Double.parseDouble(txt_Num1.getText().toString());
double Op2=Double.parseDouble(txt_Num2.getText().toString());
double Res;
if (v.equals(but_Add))
Res=Op1+Op2;
else if(v.equals(but_Sub))
Res=Op1-Op2;
else if(v.equals(but_Mul))
Res=Op1*Op2;
else if(v.equals(but_Div))
Res=Op1/Op2;
else
Res=0;
txt_Res.setText(String.valueOf(Res));
}
}