C++ programs to convert decimal to binary have been shown here. Both the iterative and recursive approaches have been covered.

1. C++ Program to convert decimal to binary

Code has been copied
/****************************************
alphabetacoder.com
C++ program to convert decimal to binary
*****************************************/

#include <iostream>

using namespace std;

int main() {
// declare variables
long num;
int bin[31] = {0};
int i, n = 0;

// take input
cout << "Enter the number in decimal: ";
cin >> num;

// convert the number in binary
//store the result in an array
// binary number would be stored
// in reverse order
while (num > 0) {
bin[n] = num % 2;
n++;
num = num / 2;
}

// display the number in binary
cout << "Binary: ";
for (i = n - 1; i >= 0; i--) {
cout << bin[i];
}

// new line
cout << endl;

return 0;
}


Output

Enter the number in decimal: 93

Binary: 1011101

2. C++ Program to convert decimal to binary using recursion

Code has been copied
/******************************
alphabetacoder.com
C++ program to convert decimal
to binary using recursion
*******************************/

#include <iostream>

using namespace std;

// recursive function to display
// decimal to binary
void decimal_to_binary(long num) {
if (num > 1) {
// call the function
decimal_to_binary(num / 2);
}
// display binary digit
cout << (num % 2);
}

int main() {
// declare variables
long num;

// take input
cout << "Enter the number in decimal: ";
cin >> num;

cout << "Binary: ";
// call function to display
// the decimal number in binary
// display the number in binary
decimal_to_binary(num);

// new line
cout << endl;

return 0;
}


Output

Enter the number in decimal: 17

Binary: 10001