View Compilation Error

0_0_5031218_23817.cpp: In function `int main()':
0_0_5031218_23817.cpp:18: error: `greater' undeclared (first use this function)
0_0_5031218_23817.cpp:18: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_5031218_23817.cpp:18: error: expected primary-expression before "int"
0_0_5031218_23817.cpp:25: error: expected primary-expression before "int"