View Compilation Error

0_0_4914410_30568.cpp: In function `int main()':
0_0_4914410_30568.cpp:17: error: `len' undeclared (first use this function)
0_0_4914410_30568.cpp:17: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4914410_30568.cpp:29: error: `d' undeclared (first use this function)
0_0_4914410_30568.cpp:59: error: expected init-declarator before '<' token
0_0_4914410_30568.cpp:59: error: expected `,' or `;' before '<' token
0_0_4914410_30568.cpp:59: error: expected `;' before ')' token