scanf("%s",ch+1);转为c++

Null is a term used to indicate the absence of a value or a non-existent object or condition. In programming, null often refers to a variable or object that has not been assigned a value or a reference. It is used to represent the absence of data or the lack of a valid value. When a variable or object is assigned a null value, it means that it does not contain any data or reference to an object. In databases, null is used to indicate the absence of a value in a field or column.