countdown_timer.c(119): error C100: unprintable character 0x97 skipped

SetSec—;

SetSec--;

181  if(m>0)             // if minute is greater then zero
182 {
183 m–;                              // minute is decrease till zero
184 s=-1 ;                          // after releasing minute decrease button seconds initialize from   
185 }
186 }
187 else if(r==0)          // switch for decreasing hours
188 {
189 if(h>0)                // if hour is greater than zero
190 {
191 h–;                      // hour is decrease till zero
      s=-1;                    // after releasing hour decrease button seconds initialize from zero
      }
      }
      else if(l==0)             // switch for increasing minutes
      {
      m++;
      s=-1;
      if(m>60)                  // if increased minutes are above than 60 than it again start from zero
      {
      m=0;
       s=-1;
       }
       }
       else if(t==0)           // switch for increasing days
       {
       i++;