View Compilation Error

0_0_22030635_20747.c: In function 'main':
0_0_22030635_20747.c:7:2: error: expected expression before '/' token
  // 正整数
  ^
0_0_22030635_20747.c:7:2: error: stray '\325' in program
0_0_22030635_20747.c:7:2: error: stray '\375' in program
0_0_22030635_20747.c:7:2: error: stray '\325' in program
0_0_22030635_20747.c:7:2: error: stray '\373' in program
0_0_22030635_20747.c:7:2: error: stray '\312' in program
0_0_22030635_20747.c:7:2: error: stray '\375' in program
0_0_22030635_20747.c:9:22: error: 'n' undeclared (first use in this function)
  while (scanf("%d", &n) != EOF && n >= 1 && n <= 1e18)
                      ^
0_0_22030635_20747.c:9:22: note: each undeclared identifier is reported only once for each function it appears in
0_0_22030635_20747.c:11:10: error: 'k' undeclared (first use in this function)
   while (k <= n)
          ^
0_0_22030635_20747.c:15:5: error: 'sum' undeclared (first use in this function)
     sum++;
     ^