convert this C++ code to a C language code(make sure it ruins properly):

#include

using namespace std;

string decToBin(int num)

{

/*

Converts a given decimal number to a binary number.

*/

if (num == 0) return "0";

if (num == 1) return "1";

if (num % 2 == 0)

return decToBin(num / 2) + "0"; // call then add to combin the letters in reverse.

else

return decToBin(num / 2) + "1"; // call then add to combin the letters in reverse.

}

int modExp(int b, int e, int m) {

/*

Calculates modular exponentiation: b^n mod m

*/

int x, power;

x = 1;

power = b % m;

string binaryNum = decToBin(e); // convert e to a binary string.

for (int i = binaryNum.size() - 1; i >= 0; i--) { // iterate over each char of the bianry number

char c = binaryNum[i];

cout << "Because b" << binaryNum.size() - 1 - i << " is " << string(1, c) << ", we have x = ";

if (c == '1') { // print (x * power) if c == 1

cout << "(" << x << " * " << power << ") ";

}

else {

cout << x;

}

if (i == 0) {

cout << " mod " << m << " ==> "; // if it is the last iteration

}

else {

cout << " and power = " << power << " ^ " << 2 << " mod " << m << " = " << (power * power) % m << " ";

}

if (c == '1')

x = (x * power) % m;

power = (power * power) % m;

}

return x;

}

int main() {

int a, b, m;

cout << "MODULAR EXPONENTIATION CALCULATOR ";

cout << "(a ^ b mod m solver) ";

//ask user for input

cout << "Enter Base (a): ";

cin >> a;

cout << "Enter Exponent (b): ";

cin >> b;

cout << "Enter Modulus (m): ";

cin >> m;

cout << b << " is equivalent to (" << decToBin(b) << ") as binary number... ";

// apply operation

int result = modExp(a, b, m);

//print result

cout << " MODULAR EXPONENTIATION of (" << a << "^" << b << ") mod (" << m << ") = " << result << " ";

}