View Compilation Error

0_0_3831157_32326.cpp: In function `int main()':
0_0_3831157_32326.cpp:7: error: `cin' undeclared (first use this function)
0_0_3831157_32326.cpp:7: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_3831157_32326.cpp:10: error: `r' undeclared (first use this function)