valid number

bool isNumber(const char *s) {
    while(*s == ' ') s++;//消除空格
    
    if(*s == '+' || *s == '-') s++;
    
    //检测小数点
    int n_nm, p_nm;
    for(n_nm = 0, p_nm =0; (*s >= '0' && *s <= '9')||(*s == '.'); s++){
        if(*s == '.') p_nm++;
        else if(*s >= '0' && *s <= '9') n_nm++;
    }
    if(p_nm > 1 || n_nm < 1) return false;
    
    //检测e
    if(*s == 'e' || *s == 'E'){
        n_nm = 0;
        s++;
        if(*s == '+' || *s == '-')s++;
        while(*s >= '0' && *s <= '9'){
            n_nm++;
            s++;
        }
        if(n_nm < 1) return false;
    }
    
    //消除空格
    while(*s == ' ')s++;
    
    return *s == 0;
}