Valid Number
Desicription
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.
Solution
代码语言:javascript复制class Solution {
public:
bool isNumber(string s) {
int index = 0;
for(; s[index] == ' '; index );
if(s[index] == ' ' || s[index] == '-')
index ;
int n_num = 0, n_pt = 0;
for(; ((s[index] <= '9' && s[index] >= '0') || s[index] == '.'); index )
s[index] == '.'?n_pt :n_num ;
if(!n_num || n_pt > 1)
return 0;
if(s[index] == 'e'){
index ;
if(s[index] == ' ' || s[index] == '-')
index ;
int n_num = 0;
for(; s[index] >= '0' && s[index] <= '9'; index )
n_num ;
if(!n_num)
return 0;
}
for(; s[index] == ' '; index );
return !s[index];
}
};