/in/foo.c: In function 'main':
/in/foo.c:16:8: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
        if(s[1]>=s[0]&& 0<=s[1]&&s[1]<=30&&0<=s[0]&&s[0]<=30)
        ^~
/in/foo.c:18:10: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
          printf("%d",sum);
          ^~~~~~
/in/foo.c:6:12: warning: variable 't2' set but not used [-Wunused-but-set-variable]
    char t1,t2;
            ^~
/in/foo.c:6:9: warning: variable 't1' set but not used [-Wunused-but-set-variable]
    char t1,t2;
         ^~
/in/foo.c:18:10: warning: 'sum' may be used uninitialized in this function [-Wmaybe-uninitialized]
          printf("%d",sum);
          ^~~~~~~~~~~~~~~~