﻿ Java exercises: Convert a decimal number to binary numbers - w3resource

# Java Exercises: Convert a decimal number to binary numbers

## Java Basic: Exercise-19 with Solution

Write a Java program to convert a decimal number to binary number.

Decimal number: The decimal numeral system is the standard system for denoting integer and non-integer numbers. It is also called base-ten positional numeral system.

Binary number: In digital electronics and mathematics, a binary number is a number expressed in the base-2 numeral system or binary numeral system. This system uses only two symbols: typically 1 (one) and 0 (zero).

Test Data:
Input a Decimal Number : 5

Pictorial Presentation: of decimal to binary number

Sample Solution:

Java Code:

``````import java.util.Scanner;
public class Exercise19 {
public static void main(String args[])
{
int dec_num, quot, i=1, j;
int bin_num[] = new int[100];
Scanner scan = new Scanner(System.in);

System.out.print("Input a Decimal Number : ");
dec_num = scan.nextInt();

quot = dec_num;

while(quot != 0)
{
bin_num[i++] = quot%2;
quot = quot/2;
}

System.out.print("Binary number is: ");
for(j=i-1; j>0; j--)
{
System.out.print(bin_num[j]);
}
System.out.print("\n");
}
}
```
```

Sample Output:

```Input a Decimal Number : 5
Binary number is: 101
```

Flowchart:

Java Code Editor:

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## Java: Tips of the Day

A Simple IO:

In order to read from a file and write to a file, Java offers FileInputStream and FileOutputStream Classes. FileInputStream's constructor accepts filepath of Input File as argument and creates File Input Stream. Similarly, FileOutputStream's constructor accepts filepath of Output File as argument and creates File Output Stream.After the file handling is done, it's important to "close" the streams.

```import java.io.*;

public class myIODemo {
public static void main(String args[]) throws IOException {
FileInputStream in = null;
FileOutputStream out = null;

try {
in = new FileInputStream("//home//user//Documents//InputFile.txt");
out = new FileOutputStream("//home//user//Documents//OutputFile.txt");

int c;
while((c = in.read()) != -1) {
out.write(c);
}
} finally {
if(in != null) {
in.close();
}
if(out != null) {
out.close();
}
}
}
}
```

Ref: https://bit.ly/3nwqLNg