foo.cpp:22:6: error: empty character constant
 case '':z=(xy)%M;break;
      ^
foo.cpp:40:6: error: empty character constant
 case '':x=3;break;
      ^
foo.cpp:51:6: error: empty character constant
 case '':y=3;break;
      ^
foo.cpp:1:1: error: 'include' does not name a type
 include <iostream> include <cstring> include <cstdio> include <cstdlib>
 ^
foo.cpp: In function 'int cc(int, char, int)':
foo.cpp:22:12: error: 'xy' was not declared in this scope
 case '':z=(xy)%M;break;
            ^
foo.cpp:28:4: error: 'zx' was not declared in this scope
 z=(zx)%M;
    ^
foo.cpp: In function 'int count(int, char*)':
foo.cpp:70:22: error: 'd10' was not declared in this scope
 else{d=opd[topd--];d=d10+s[i]-'0';opd[++topd]=d;}
                      ^
foo.cpp: In function 'int main()':
foo.cpp:103:9: error: 'gets' was not declared in this scope
 gets(tmp);
         ^
foo.cpp:104:15: error: 'strlen' was not declared in this scope
 tmp[strlen(tmp)]='#';
               ^
foo.cpp:105:1: error: 'cin' was not declared in this scope
 cin>>n;
 ^
foo.cpp:107:15: error: 'scanf' was not declared in this scope
 scanf("%c",&aa);
               ^
foo.cpp:124:33: error: 'printf' was not declared in this scope
 if(!flagg[i])printf("%c",'A'+i-1);
                                 ^