View Compilation Error

0_0_6020923_21659.cpp: In function `int main()':
0_0_6020923_21659.cpp:24: error: `core_insert' undeclared (first use this function)
0_0_6020923_21659.cpp:24: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_6020923_21659.cpp:26: error: `core_delete' undeclared (first use this function)
0_0_6020923_21659.cpp:15: error: too many arguments to function `int core_find(int)'
0_0_6020923_21659.cpp:29: error: at this point in file
0_0_6020923_21659.cpp: In function `void core_insert(int)':
0_0_6020923_21659.cpp:37: error: `void core_insert(int)' used prior to declaration
0_0_6020923_21659.cpp: In function `void core_delete(int)':
0_0_6020923_21659.cpp:40: error: `void core_delete(int)' used prior to declaration