View Compilation Error

2_29342_2316944_4335.c:1:1: error: expected identifier or '(' before '/' token
 //#include<iostream>
 ^
2_29342_2316944_4335.c:1:3: error: stray '#' in program
 //#include<iostream>
   ^
In file included from 4.9.2/x86_64-w64-mingw32/include/_mingw.h:282:0,
                 from 4.9.2/x86_64-w64-mingw32/include/crtdefs.h:10,
                 from 4.9.2/x86_64-w64-mingw32/include/stdio.h:9,
                 from 2_29342_2316944_4335.c:2:
4.9.2/x86_64-w64-mingw32/include/vadefs.h:29:11: error: unknown type name '__gnuc_va_list'
   typedef __gnuc_va_list va_list;
           ^
2_29342_2316944_4335.c:4:1: error: unknown type name 'using'
 using namespace std;
 ^
2_29342_2316944_4335.c:4:17: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'std'
 using namespace std;
                 ^
2_29342_2316944_4335.c: In function 'main':
2_29342_2316944_4335.c:11:18: error: expected expression before '/' token
  scanf("%d", &t);//cin>>t;
                  ^
2_29342_2316944_4335.c:14:28: error: expected expression before '/' token
   scanf("%ld %ld", &n, &m);//cin>>n>>m;
                            ^
2_29342_2316944_4335.c:17:24: error: expected expression before '/' token
    scanf("%ld", &a[j]);//cin>>a[j];
                        ^
2_29342_2316944_4335.c:24:4: error: expected expression before '/' token
    //cin>>l>>r;
    ^
2_29342_2316944_4335.c:25:4: error: expected expression before '/' token
    //cout<<a[r]-a[l-1]<<endl;
    ^