View Compilation Error

0_0_30214236_24195\Main.java:1: 错误: 非法字符: '#'
#include<stdio.h>
^
0_0_30214236_24195\Main.java:1: 错误: 需要class, interface或enum
#include<stdio.h>
        ^
0_0_30214236_24195\Main.java:2: 错误: 非法字符: '#'
#include<math.h>
^
0_0_30214236_24195\Main.java:3: 错误: 非法字符: '#'
#include<string.h>
^
0_0_30214236_24195\Main.java:4: 错误: 非法字符: '#'
#define PI acos(-1.0)
^
0_0_30214236_24195\Main.java:8: 错误: 需要class, interface或enum
    while(~scanf("%lf",&n))
    ^
0_0_30214236_24195\Main.java:11: 错误: 需要class, interface或enum
        S=(n-1)/2*sin(2*PI/n)+sin(PI/n);
        ^
0_0_30214236_24195\Main.java:12: 错误: 需要class, interface或enum
        printf("%.6lf\n",S);
        ^
0_0_30214236_24195\Main.java:13: 错误: 需要class, interface或enum
    }
    ^
0_0_30214236_24195\Main.java:15: 错误: 需要class, interface或enum
}
^
10 个错误