foo.cc: In function 'int main()':
foo.cc:19:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %s %c %f",&s[i].sno,s[i].sname,&s[i].sex,&s[i].score);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:16:8: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int i,a,b;
        ^
foo.cc:16:10: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int i,a,b;
          ^

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