问题描述:
请实现一个函数用来判断字符串是否表示数值(包括整数和小数)。例如,字符串"+100","5e2","-123","3.1416"和"-1E-16"都表示数值。 但是"12e","1a3.14","1.2.3","+-5"和"12e+4.3"都不是。
class Solution {
public:
char arr[10] = "+-n.ne+-n";
int turn[10][9] = {
//+ - n . n e + - n
{1, 1, 1, 0, 0, 0, 0, 0, 0}, // # start
{0, 0, 1, 1, 0, 0, 0, 0, 0}, // +
{0, 0, 1, 1, 0, 0, 0, 0, 0}, // -
{0, 0, 1, 1, 0, 1, 0, 0, 0}, // n
{0, 0, 0, 0, 1, 0, 0, 0, 0}, // .
{0, 0, 0, 0, 1, 1, 0, 0, 0}, // n
{0, 0, 0, 0, 0, 0, 1, 1, 1}, // e
{0, 0, 0, 0, 0, 0, 0, 0, 1}, // +
{0, 0, 0, 0, 0, 0, 0, 0, 1}, // -
{0, 0, 0, 0, 0, 0, 0, 0, 1} // n
};
bool isNumeric(char* string) {
int cur = 0;
for(int j, i = 0; string[i]; i++) {
for(j = 0; j < 9; j++) {
if(turn[cur][j]) {
if(('0' <= string[i] && string[i] <= '9' && arr[j] == 'n') ||
(string[i] == 'E' && arr[j] == 'e')||
string[i] == arr[j]) {
cur = j + 1;
break;
}
}
}
if(j == 9) return false;
}
if(cur == 3 || cur == 4 || cur == 5 || cur == 9)
return true;
return false;
}
};