#define N 10 is a pre-compiler directive. Before compilation, all occurrences of N will be replaced by 10. Therefore, in the code int x[N], it will...

1/a = 0, if it is forcibly converted to float, it will be 0.0.

The results of the relational expressions (such as &, |, ~) and logical expressions (such as &&, ||) are represented by 0 or 1.

It must consist of digits, letters and underscores. And it cannot start with a digit!