Language: C++

#include <stdio.h>

int main(){
  int X;
    int Y;

  
  switch(scanf()){
   case:"A"
     X = 10;
      break;
   case:"B"
     X = 11;
      break;
   case:"C"
     X = 12;
      break;
   case:"D"
     X = 13;
      break;
   case:"E"
     X = 14;
      break;
   case:"F"
     X = 15;
      break;
  }
  
  switch(scanf()){
   case:"A"
     Y = 10;
      break;
   case:"B"
     Y = 11;
      break;
   case:"C"
     Y = 12;
      break;
   case:"D"
     Y = 13;
      break;
   case:"E"
     Y = 14;
      break;
   case:"F"
     Y = 15;
      break;
  }
  
  int d = X-Y;
  
  if(d > 0){
    println(">");
  }
  else if(d < 0){
    println("<");
  }
  else if(d = 0){
  println("=");
  }
  retrun();
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:15: error: too few arguments to function 'int scanf(const char*, ...)'
    8 |   switch(scanf()){
      |          ~~~~~^~
In file included from /usr/include/features.h:523,
                 from /usr/include/x86_64-linux-gnu/bits/libc-header-start.h:33,
                 from /usr/include/stdio.h:28,
                 from a.cc:1:
/usr/include/stdio.h:445:12: note: declared here
  445 | extern int __REDIRECT (scanf, (const char *__restrict __format, ...),
      |            ^~~~~~~~~~
a.cc:9:8: error: expected primary-expression before ':' token
    9 |    case:"A"
      |        ^
a.cc:9:12: error: expected ';' before 'X'
    9 |    case:"A"
      |            ^
      |            ;
   10 |      X = 10;
      |      ~      
a.cc:12:8: error: expected primary-expression before ':' token
   12 |    case:"B"
      |        ^
a.cc:12:12: error: expected ';' before 'X'
   12 |    case:"B"
      |            ^
      |            ;
   13 |      X = 11;
      |      ~      
a.cc:15:8: error: expected primary-expression before ':' token
   15 |    case:"C"
      |        ^
a.cc:15:12: error: expected ';' before 'X'
   15 |    case:"C"
      |            ^
      |            ;
   16 |      X = 12;
      |      ~      
a.cc:18:8: error: expected primary-expression before ':' token
   18 |    case:"D"
      |        ^
a.cc:18:12: error: expected ';' before 'X'
   18 |    case:"D"
      |            ^
      |            ;
   19 |      X = 13;
      |      ~      
a.cc:21:8: error: expected primary-expression before ':' token
   21 |    case:"E"
      |        ^
a.cc:21:12: error: expected ';' before 'X'
   21 |    case:"E"
      |            ^
      |            ;
   22 |      X = 14;
      |      ~      
a.cc:24:8: error: expected primary-expression before ':' token
   24 |    case:"F"
      |        ^
a.cc:24:12: error: expected ';' before 'X'
   24 |    case:"F"
      |            ^
      |            ;
   25 |      X = 15;
      |      ~      
a.cc:29:15: error: too few arguments to function 'int scanf(const char*, ...)'
   29 |   switch(scanf()){
      |          ~~~~~^~
/usr/include/stdio.h:445:12: note: declared here
  445 | extern int __REDIRECT (scanf, (const char *__restrict __format, ...),
      |            ^~~~~~~~~~
a.cc:30:8: error: expected primary-expression before ':' token
   30 |    case:"A"
      |        ^
a.cc:30:12: error: expected ';' before 'Y'
   30 |    case:"A"
      |            ^
      |            ;
   31 |      Y = 10;
      |      ~      
a.cc:33:8: error: expected primary-expression before ':' token
   33 |    case:"B"
      |        ^
a.cc:33:12: error: expected ';' before 'Y'
   33 |    case:"B"
      |            ^
      |            ;
   34 |      Y = 11;
      |      ~      
a.cc:36:8: error: expected primary-expression before ':' token
   36 |    case:"C"
      |        ^
a.cc:36:12: error: expected ';' before 'Y'
   36 |    case:"C"
      |            ^
      |            ;
   37 |      Y = 12;
      |      ~      
a.cc:39:8: error: expected primary-expression before ':' token
   39 |    case:"D"
      |        ^
a.cc:39:12: error: expected ';' before 'Y'
   39 |    case:"D"
      |            ^
      |            ;
   40 |      Y = 13;
      |      ~      
a.cc:42:8: error: expected primary-expression before ':' token
   42 |    case:"E"
      |        ^
a.cc:42:12: error: expected ';' before 'Y'
   42 |    case:"E"
      |            ^
      |            ;
   43 |      Y = 14;
      |      ~      
a.cc:45:8: error: expected primary-expression before ':' token
   45 |    case:"F"
      |        ^
a.cc:45:12: error: expected ';' before 'Y'
   45 |    case:"F"
      |            ^
      |            ;
   46 |      Y = 15;
      |      ~      
a.cc:53:5: error: 'println' was not declared in this scope; did you mean 'printf'?
   53 |     println(">");
      |     ^~~~~~~
      |     printf
a.cc:56:5: error: 'println' was not declared in this scope; did you mean 'printf'?
   56 |     println("<");
      |     ^~~~~~~
      |     printf
a.cc:59:3: error: 'println' was not declared in this scope; did you mean 'printf'?
   59 |   println("=");
      |   ^~~~~~~
      |   printf
a.cc:61:3: error: 'retrun' was not declared in this scope
   61 |   retrun();
      |   ^~~~~~