View Compilation Error

0_0_37083806_2470.cpp: In function 'int main()':
0_0_37083806_2470.cpp:19:13: error: 'max' was not declared in this scope
 lx=max(x1,x3);
             ^
0_0_37083806_2470.cpp:21:13: error: 'min' was not declared in this scope
 rx=min(x2,x4);
             ^