Language: C++

#include<iostream>
#include <math.h>
using namespace std;
 
main(){ 
   int S;
   int h,m,s;
 
   cin >> S;
 
   s = S%60;
??????m = floor((float) S / 60) %60;
??????h = floor((float) S / 60 / 60);
 
   cout << h << ":" << m << ":" << s << endl;
   return 0;
}

Compiler output:
a.cc:5:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
    5 | main(){
      | ^~~~
a.cc: In function 'int main()':
a.cc:12:1: error: expected primary-expression before '?' token
   12 | ??????m = floor((float) S / 60) %60;
      | ^
a.cc:12:2: error: expected primary-expression before '?' token
   12 | ??????m = floor((float) S / 60) %60;
      |  ^
a.cc:12:3: error: expected primary-expression before '?' token
   12 | ??????m = floor((float) S / 60) %60;
      |   ^
a.cc:12:4: error: expected primary-expression before '?' token
   12 | ??????m = floor((float) S / 60) %60;
      |    ^
a.cc:12:5: error: expected primary-expression before '?' token
   12 | ??????m = floor((float) S / 60) %60;
      |     ^
a.cc:12:6: error: expected primary-expression before '?' token
   12 | ??????m = floor((float) S / 60) %60;
      |      ^
a.cc:12:33: error: invalid operands of types 'float' and 'int' to binary 'operator%'
   12 | ??????m = floor((float) S / 60) %60;
      |           ~~~~~~~~~~~~~~~~~~~~~ ^~~
      |                |                 |
      |                float             int
a.cc:12:36: error: expected ':' before ';' token
   12 | ??????m = floor((float) S / 60) %60;
      |                                    ^
      |                                    :
a.cc:12:36: error: expected primary-expression before ';' token
a.cc:12:36: error: expected ':' before ';' token
   12 | ??????m = floor((float) S / 60) %60;
      |                                    ^
      |                                    :
a.cc:12:36: error: expected primary-expression before ';' token
a.cc:12:36: error: expected ':' before ';' token
   12 | ??????m = floor((float) S / 60) %60;
      |                                    ^
      |                                    :
a.cc:12:36: error: expected primary-expression before ';' token
a.cc:12:36: error: expected ':' before ';' token
   12 | ??????m = floor((float) S / 60) %60;
      |                                    ^
      |                                    :
a.cc:12:36: error: expected primary-expression before ';' token
a.cc:12:36: error: expected ':' before ';' token
   12 | ??????m = floor((float) S / 60) %60;
      |                                    ^
      |                                    :
a.cc:12:36: error: expected primary-expression before ';' token
a.cc:12:36: error: expected ':' before ';' token
   12 | ??????m = floor((float) S / 60) %60;
      |                                    ^
      |                                    :
a.cc:12:36: error: expected primary-expression before ';' token
a.cc:13:1: error: expected primary-expression before '?' token
   13 | ??????h = floor((float) S / 60 / 60);
      | ^
a.cc:13:2: error: expected primary-expression before '?' token
   13 | ??????h = floor((float) S / 60 / 60);
      |  ^
a.cc:13:3: error: expected primary-expression before '?' token
   13 | ??????h = floor((float) S / 60 / 60);
      |   ^
a.cc:13:4: error: expected primary-expression before '?' token
   13 | ??????h = floor((float) S / 60 / 60);
      |    ^
a.cc:13:5: error: expected primary-expression before '?' token
   13 | ??????h = floor((float) S / 60 / 60);
      |     ^
a.cc:13:6: error: expected primary-expression before '?' token
   13 | ??????h = floor((float) S / 60 / 60);
      |      ^
a.cc:13:37: error: expected ':' before ';' token
   13 | ??????h = floor((float) S / 60 / 60);
      |                                     ^
      |                                     :
a.cc:13:37: error: expected primary-expression before ';' token
a.cc:13:37: error: expected ':' before ';' token
   13 | ??????h = floor((float) S / 60 / 60);
      |                                     ^
      |                                     :
a.cc:13:37: error: expected primary-expression before ';' token
a.cc:13:37: error: expected ':' before ';' token
   13 | ??????h = floor((float) S / 60 / 60);
      |                                     ^
      |                                     :
a.cc:13:37: error: expected primary-expression before ';' token
a.cc:13:37: error: expected ':' before ';' token
   13 | ??????h = floor((float) S / 60 / 60);
      |                                     ^
      |                                     :
a.cc:13:37: error: expected primary-expression before ';' token
a.cc:13:37: error: expected ':' before ';' token
   13 | ??????h = floor((float) S / 60 / 60);
      |                                     ^
      |                                     :
a.cc:13:37: error: expected primary-expression before ';' token
a.cc:13:37: error: expected ':' before ';' token
   13 | ??????h = floor((float) S / 60 / 60);
      |                                     ^
      |                                     :
a.cc:13:37: error: expected primary-expression before ';' token