Language: C

main(y,m,d){for(gets(&y);~scanf("%d%d%d",&y,&m,&d);printf("%d\n",196471-(--y)*195-y/3*5-(--m)*20+(y%3-2?m/2:0)-d));exit(0);}

Compiler output:
main.c:1:1: error: return type defaults to 'int' [-Wimplicit-int]
    1 | main(y,m,d){for(gets(&y);~scanf("%d%d%d",&y,&m,&d);printf("%d\n",196471-(--y)*195-y/3*5-(--m)*20+(y%3-2?m/2:0)-d));exit(0);}
      | ^~~~
main.c: In function 'main':
main.c:1:1: error: type of 'y' defaults to 'int' [-Wimplicit-int]
main.c:1:1: error: type of 'm' defaults to 'int' [-Wimplicit-int]
main.c:1:1: error: type of 'd' defaults to 'int' [-Wimplicit-int]
main.c:1:17: error: implicit declaration of function 'gets' [-Wimplicit-function-declaration]
    1 | main(y,m,d){for(gets(&y);~scanf("%d%d%d",&y,&m,&d);printf("%d\n",196471-(--y)*195-y/3*5-(--m)*20+(y%3-2?m/2:0)-d));exit(0);}
      |                 ^~~~
main.c:1:27: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    1 | main(y,m,d){for(gets(&y);~scanf("%d%d%d",&y,&m,&d);printf("%d\n",196471-(--y)*195-y/3*5-(--m)*20+(y%3-2?m/2:0)-d));exit(0);}
      |                           ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | main(y,m,d){for(gets(&y);~scanf("%d%d%d",&y,&m,&d);printf("%d\n",196471-(--y)*195-y/3*5-(--m)*20+(y%3-2?m/2:0)-d));exit(0);}
main.c:1:27: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    1 | main(y,m,d){for(gets(&y);~scanf("%d%d%d",&y,&m,&d);printf("%d\n",196471-(--y)*195-y/3*5-(--m)*20+(y%3-2?m/2:0)-d));exit(0);}
      |                           ^~~~~
main.c:1:27: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:1:52: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    1 | main(y,m,d){for(gets(&y);~scanf("%d%d%d",&y,&m,&d);printf("%d\n",196471-(--y)*195-y/3*5-(--m)*20+(y%3-2?m/2:0)-d));exit(0);}
      |                                                    ^~~~~~
main.c:1:52: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:1:52: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
main.c:1:52: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:1:116: error: implicit declaration of function 'exit' [-Wimplicit-function-declaration]
    1 | main(y,m,d){for(gets(&y);~scanf("%d%d%d",&y,&m,&d);printf("%d\n",196471-(--y)*195-y/3*5-(--m)*20+(y%3-2?m/2:0)-d));exit(0);}
      |                                                                                                                    ^~~~
main.c:1:1: note: include '<stdlib.h>' or provide a declaration of 'exit'
  +++ |+#include <stdlib.h>
    1 | main(y,m,d){for(gets(&y);~scanf("%d%d%d",&y,&m,&d);printf("%d\n",196471-(--y)*195-y/3*5-(--m)*20+(y%3-2?m/2:0)-d));exit(0);}
main.c:1:116: warning: incompatible implicit declaration of built-in function 'exit' [-Wbuiltin-declaration-mismatch]
    1 | main(y,m,d){for(gets(&y);~scanf("%d%d%d",&y,&m,&d);printf("%d\n",196471-(--y)*195-y/3*5-(--m)*20+(y%3-2?m/2:0)-d));exit(0);}
      |                                                                                                                    ^~~~
main.c:1:116: note: include '<stdlib.h>' or provide a declaration of 'exit'