"Leetcode" "Hard" Valid number

Validate if a given string is numeric.

Some Examples:
"0"=true
" 0.1 "=true
"abc"=false
"1 a"=false
"2e10"=true

Note:it is intended for the problem statement to be ambiguous. You should gather all requirements up front before implementing one.

The subject needs to be considered:

1, the space before the character

2. Character sign

3, check whether it is a number, the number can contain a '. ' Decimal point, the number should have at least one

4, after the number and point, check if there is ' e ', if there is:

(1) Check whether the index is positive or negative

(2) Check if there is a number, there is at least one

5, the space after the character

6. The last encounter ' \ ' returns true, otherwise false

Code:

1 classSolution {2  Public:3     BOOLIsnumber (strings) {4         inti =0;5     6         //Skip the Whilespaces7          for(; s[i] = =' '; i++) {}8     9         //Check the significandTen         if(S[i] = ='+'|| S[i] = ='-') i++;//Skip the sign if exist One      A         intn_nm, n_pt; -          for(n_nm=0, n_pt=0; (s[i]<='9'&& s[i]>='0') || s[i]=='.'; i++) -S[i] = ='.'? n_pt++:n_nm++;  the         if(n_pt>1|| n_nm<1)//no more than one point, at least one digit -             return false; -      -         //Check the exponent if exist +         if(S[i] = ='e') { -i++; +             if(S[i] = ='+'|| S[i] = ='-') i++;//Skip The Sign A      at             intN_NM =0; -              for(; s[i]>='0'&& s[i]<='9'; i++, n_nm++) {} -             if(n_nm<1) -                 return false; -         } -      in         //Skip the trailing whitespaces -          for(; s[i] = =' '; i++) {} to      +         returns[i]==0;//must reach the ending 0 of the string -     } the};

"Leetcode" "Hard" Valid number