The return value is 0 or 1, where 0 means false and non-zero means true. For example! 0 returns 1, 0&; & kloc-0/returns 0,0 || 1 returns1.

A relational expression means that the operator is

The return value is also 0 or 1, such as a! =b, a & gt=0, etc.

A meaningful expression that connects relational expressions or logical quantities with logical operators is called a logical expression. The value of a logical expression is a logical value, that is, "true" or "false". C language compiler system uses the number 1 to indicate "true" and the number 0 to indicate "false" when giving the logical operation result, but when judging whether a quantity is "true", it uses 0 to indicate "false" and non-0 to indicate "true".

You can assign the operation result of a logical expression (0 or 1) to an integer variable or a character variable.

In C language, it is equal to "= =", but not equal to "! ="。