Program to Convert Decimal to Binary in C++ (vice versa)

 

1. Program to convert Decimal to Binary in C++

In this program, we will ask the user to enter the number which user wants to convert into binary.

Decimal to Binary Conversion Algorithm:

1 Step: At first divide the number by 2 by using modulus operator ‘%’ and store the remainder in the array.

2 Step: divide that number by 2.

3 Step: Now repeat the step until the number is greater than 0.

C++

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//Learnprogramo - programming made simple

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#include <iostream>

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#include <cmath>

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using namespace std;

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long long convertDecimalToBinary(int);

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int main()

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{

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    int n, binaryNumber;

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    cout << "Enter a decimal number: ";

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    cin >> n;

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    binaryNumber = convertDecimalToBinary(n);

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    cout << n << " in decimal = " << binaryNumber << " in binary" << endl ;

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    return 0;

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}

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long long convertDecimalToBinary(int n)

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{

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    long long binaryNumber = 0;

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    int remainder, i = 1, step = 1;

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    while (n!=0)

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    {

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        remainder = n%2;

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        cout << "Step " << step++ << ": " << n << "/2, Remainder = " << remainder << ", Quotient = " << n/2 << endl;

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        n /= 2;

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        binaryNumber += remainder*i;

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        i *= 10;

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    }

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    return binaryNumber;

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}

Output:

2. Program to Convert Binary to Decimal in C++

In this program, we will convert the Binary input to Decimal.

Binary to Decimal Conversion Algorithm:

1 Step: Take a Binary Input to convert into Decimal.

2 Step: Multiply each binary digit starting from last with the power of 2 i.e(2^0,2^1).

3 Step: make an addition of the multiplied digits.

4 Step: Thus the addition gives the Decimal output.

C++

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//Learnprogramo - programming made simple

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#include <iostream>

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#include <cmath>

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using namespace std;

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int convertBinaryToDecimal(long long);

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int main()

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{

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    long long n;

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    cout << "Enter a binary number: ";

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    cin >> n;

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    cout << n << " in binary = " << convertBinaryToDecimal(n) << "in decimal";

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    return 0;

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}

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int convertBinaryToDecimal(long long n)

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{

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    int decimalNumber = 0, i = 0, remainder;

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    while (n!=0)

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    {

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        remainder = n%10;

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        n /= 10;

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        decimalNumber += remainder*pow(2,i);

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        ++i;

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    }

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    return decimalNumber;

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}

Output:

3. Decimal to Binary Conversion Using Bitwise Operator

C++

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//Learnprogramo - programming made simple

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#include <iostream> 

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using namespace std; 

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int decToBinary(int n) 

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{ 

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    for (int i = 31; i >= 0; i--) { 

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        int k = n >> i; 

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        if (k & 1) 

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            cout << "1"; 

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        else

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            cout << "0"; 

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    } 

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} 

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int main() 

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{ 

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    //size of integer asumed as 32 bits

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    int n = 32; 

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    decToBinary(n); 

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} 

Output:

4. Decimal to Binary Without Using Array

C++

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//Learnprogramo - programming made simple

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#include <cmath> 

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#include <iostream> 

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using namespace std; 

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#define ull unsigned long long int 

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int decimalToBinary(int N) 

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{

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    ull B_Number = 0; 

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    int cnt = 0; 

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    while (N != 0) { 

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        int rem = N % 2; 

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        ull c = pow(10, cnt); 

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        B_Number += rem * c; 

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        N /= 2; 

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        cnt++; 

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    } 

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    return B_Number; 

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} 

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int main() 

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{ 

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    int N = 15; 

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    cout << decimalToBinary(N); 

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    return 0; 

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} 

Output: