hi. how can a decimal value be converted to binary in a c++ program?

Division by two with reminder.
divide % the number by two till reaches Zero if the reminder is no-zero, save 1 else save 0.
then write binary number from button to above.

now you can write the code easily with forloop and if statement.

commented: plz send me the code +0
void printBinary(char ch) noexcept {
for(int i = 7; i >= 0; --i)
if(ch & (1 << i)) std::cout << "1";
else std::cout << "0";
}

int main() {
int num = 56;
std::cout << std::endl;
printBinary(num);
std::cout << std::endl;
return 0;
}

return 0;

The easiest way is to use bitset

#include <iostream>
#include <bitset>

int main ()
{
std::bitset<16> foo(123);
std::cout << foo << '\n';
return 0;
}

Mine is a bit too much using just simple for and if loops

#include<iostream>
#include<stdlib.h>

using namespace std;

int main()
{
int a[16]={0},b,i=0;
cout<<"\n Enter the number to be converted to binary";
cin>>b;
if(b==0)
{
cout<<"\n 0000";
exit(1);
}
while(b!=0){
a[i]=b%2;
b/=2;
i++;
if(b==1)
{
a[i]=1;
break;
}
}
for(int j=i;j>=0;j--)
cout<<a[j];
}