### Decimal to binary conversion in C++:

In this post, we will learn how to convert one *decimal* number to *binary*. Decimal number system is based on *10* and binary number system is based on *2*. Our program will take one number as input from the user i.e. a *decimal number* and print out its *binary representation*.

There is a simple process to convert one *decimal to binary*. It is known as *repeated division by 2*. i.e. we will divide the decimal number by *2* until no further division is possible.

### Example of decimal to binary conversion:

Suppose, we want to convert *19* to *binary*. Following are the steps required for that:

*19/2*, remainder = 1, quotient = 9*9/2*, remainder = 1, quotient = 4*4/2*, remainder = 0, quotient = 2*2/2*, remainder = 0, quotient = 1*1/2*, remainder = 1, quotient = 0

We are dividing the value of *quotient* by *2* in each step until it is *0*.

So, the binary representation of *19* is *10011*, we are taking all the remainders from *last* to *first*.

### C++ program:

```
#include <iostream>
using namespace std;
long decimalToBinary(int decimal){
long binary = 0;
int multiplier = 1;
while (decimal!=0)
{
int reminder = decimal%2;
decimal /= 2;
binary += reminder*multiplier;
multiplier *= 10;
}
return binary;
}
int main()
{
int decimal;
long binary;
cout<<"Enter the decimal value"<<endl;
cin>>decimal;
binary = decimalToBinary(decimal);
cout<<"Binary representation :"<<binary<<endl;
return 0;
}
```

### Explanation:

In this example,

*decimalToBinary*method is used to convert one decimal value to binary- We are asking the user to enter the decimal value and storing it in
*decimal*variable. *decimalToBinary*returns the binary representation in*long*format. We are storing it in*binary*variable and printing out the value.- Inside
*decimalToBinary*, we are keep dividing the value*decimal*until it become*0*. We are getting the remainder, adding it to the variable*binary*and changing it to*decimal/2*. - Once the
*while loop*ends, we are returning the value of*binary*.

### Sample Output:

```
Enter the decimal value
19
Binary representation :10011
```

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