sentinel value
nounUK /ˈsɛntɪnəl ˈvæljuː/
US /ˈsɛntənəl ˈvæljuː/
A sentinel value is a special number that tells a computer program to stop.
The program keeps reading numbers until it sees the sentinel value -1.
OTHER MEANINGS
2. A value used in a list to mark the end of the data.
The list ends with a sentinel value of 999.
3. A special value that shows a missing or unknown result.
The function returns a sentinel value when it cannot find the item.
4. A value that stands for a special condition in a data set.
In this table, -1 is a sentinel value meaning 'not recorded'.