/in/foo.c: In function 'main':
/in/foo.c:6:8: error: 'i' undeclared (first use in this function)
  while(i<=n){
        ^
/in/foo.c:6:8: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:8:4: error: 'sum' undeclared (first use in this function)
   {sum+=i;
    ^~~
/in/foo.c:10:3: warning: implicit declaration of function 'prontf' [-Wimplicit-function-declaration]
  }prontf("1到n之间能被3整除但不能被5整除的数之和为："%d\n",sum);
   ^~~~~~
/in/foo.c:10:75: error: stray '\' in program
  }prontf("1到n之间能被3整除但不能被5整除的数之和为："%d\n",sum);
                                                                           ^
/in/foo.c:10:74: error: 'd' undeclared (first use in this function)
  }prontf("1到n之间能被3整除但不能被5整除的数之和为："%d\n",sum);
                                                                          ^
/in/foo.c:10:76: error: expected ')' before 'n'
  }prontf("1到n之间能被3整除但不能被5整除的数之和为："%d\n",sum);
                                                                            ^
/in/foo.c:10:77: warning: missing terminating " character
  }prontf("1到n之间能被3整除但不能被5整除的数之和为："%d\n",sum);
                                                                             ^
/in/foo.c:10:77: error: missing terminating " character
  }prontf("1到n之间能被3整除但不能被5整除的数之和为："%d\n",sum);
                                                                             ^~~~~~~
/in/foo.c:12:4: error: expected ';' before '}' token
    }
    ^