Numeric characters' 0'-'9' are valid characters, and their ascii values are incremental and continuous. The ASCII of "0" is 48, followed by.
' 1' - 49
'2' - 50
...
Therefore, if you subtract the "0" character from a numeric character, you can get its integer value, for example:
'0'-'0'=0
' 1'-'0'= 1
...
Zhangping city is one of the cities rich in mineral resources in Fujian Province. Nearly 100 kinds of mineral resources have been discovered, such as coal, graphite, iron, le