foo.c:3:1: error: unknown type name 'bool'; did you mean '_Bool'?
 bool PAN(char a[],int i,int j)
 ^~~~
 _Bool
foo.c: In function 'PAN':
foo.c:7:23: error: 'true' undeclared (first use in this function); did you mean 'strlen'?
   if(a[x]==53) return true;
                       ^~~~
                       strlen
foo.c:7:23: note: each undeclared identifier is reported only once for each function it appears in
foo.c:9:9: error: 'false' undeclared (first use in this function); did you mean 'fclose'?
  return false;
         ^~~~~
         fclose
foo.c: In function 'main':
foo.c:15:2: warning: 'gets' is deprecated [-Wdeprecated-declarations]
  gets(a);
  ^~~~
In file included from /usr/include/stdio.h:862:0,
                 from foo.c:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:232:1: note: declared here
 gets (char *__str)
 ^~~~
foo.c:22:19: error: 'true' undeclared (first use in this function); did you mean 'strlen'?
    if(PAN(a,x,y)==true) cnt++;
                   ^~~~
                   strlen
foo.c: In function 'PAN':
foo.c:10:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
foo.c: In function 'main':
foo.c:15:2: warning: ignoring return value of 'gets', declared with attribute warn_unused_result [-Wunused-result]
  gets(a);
  ^~~~~~~

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