View Compilation Error

0_0_22122815_26946.cpp: In function 'int read()':
0_0_22122815_26946.cpp:15:39: error: 's' was not declared in this scope
  while(ch < '0' || ch > '9'){if(ch == s'-') z = -1; ch = getchar();}
                                       ^
0_0_22122815_26946.cpp:15:40: error: expected ')' before '-'
  while(ch < '0' || ch > '9'){if(ch == s'-') z = -1; ch = getchar();}
                                        ^