what does << mean in C code example

Example 1: how to use ? in c

result = comparison ? if_true : if_false;

Example 2: what is mean of define in c language

#define is a C preprocessor directive used to define macros. ... The preprocessor directives are used to provide general instruction or required data which is used inside a program. A macro is a block of code which has been given a name. Any occurance of that name is replaced by the value of the macro.