View Compilation Error

0_0_3131271_1205.cpp:20: error: `main' must return `int'
0_0_3131271_1205.cpp: In function `int main(...)':
0_0_3131271_1205.cpp:22: error: `cin' undeclared (first use this function)
0_0_3131271_1205.cpp:22: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_3131271_1205.cpp:27: error: `cout' undeclared (first use this function)
0_0_3131271_1205.cpp:27: error: `endl' undeclared (first use this function)