foo.cc: In function 'int main()':
foo.cc:40:73: warning: ' ' flag used with '%c' gnu_printf format [-Wformat=]
       printf("%-8d %-8s% -8c %-8.0f\n",s[i].num,s[i].name,"F",s[i].score);
                                                                         ^
foo.cc:40:73: warning: format '%c' expects argument of type 'int', but argument 4 has type 'const char*' [-Wformat=]
foo.cc:44:70: warning: format '%c' expects argument of type 'int', but argument 4 has type 'const char*' [-Wformat=]
    printf("%-8d %-8s %-8c %-8.0f\n",s[i].num,s[i].name,"M",s[i].score);
                                                                      ^
foo.cc:20:11: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
      scanf("%d %s %d %f",&s[i].num,s[i].name,&s[i].sex,&s[i].score);
      ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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