foo.c:1:1: error: expected identifier or '(' before numeric constant
    1 | 1 #include <iostream>
      | ^
foo.c:1:3: error: stray '#' in program
    1 | 1 #include <iostream>
      |   ^
foo.c:2:3: error: stray '#' in program
    2 | 2 #include <iomanip>
      |   ^
foo.c:4:1: error: expected identifier or '(' before numeric constant
    4 | 4 int main()
      | ^
foo.c:6:1: error: invalid suffix "cout" on integer constant
    6 | 6cout++"
      | ^~~~~
foo.c:6:8: warning: missing terminating " character
    6 | 6cout++"
      |        ^
foo.c:6:8: error: missing terminating " character
foo.c:7:1: error: invalid suffix "return" on integer constant
    7 | 7return 0：
      | ^~~~~~~
foo.c:7:9: error: invalid suffix "：" on integer constant
    7 | 7return 0：
      |         ^~~

[Hydro](https://hydro.ac)提供评测服务