foo.c: In function 'main':
foo.c:4:9: warning: unused variable 'b' [-Wunused-variable]
     int b,i,t,n;
         ^
foo.c:6:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ^~~~~~~~~~~~~~
foo.c:13:7: warning: 't' may be used uninitialized in this function [-Wmaybe-uninitialized]
     if(t!=0)
       ^

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