View Compilation Error

0_0_2957246_7185.cpp: In function `int main()':
0_0_2957246_7185.cpp:42: error: `re' undeclared (first use this function)
0_0_2957246_7185.cpp:42: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2957246_7185.cpp:42: error: expected `;' at end of input
0_0_2957246_7185.cpp:42: error: expected `}' at end of input