In most cases, variable names are chosen as short as possible. Unless the content of the variable already suggests an appropriate name, we just use the name of the data type in lowercase letters as the name of a variable of this type. When there are more such variables of one type we enumerate them starting with 0, where 0 is usually used for a variable carrying the return value.
Names for global variables are marked by a trailing underscore (_). Compared to local variables, global variables have rather long names, which should help to avoid unexpected name conflicts.