【LeetCode】1108.Defanging an IP Address

方法一：直接在“.”前后插入“[ ]”，记得要变换index

string defangIPaddr (string address) {
	for (int i = 0; i<address.size (); i++) {
		if (address[i] == '.') {
			address.insert (address.begin () + i, '[');
			address.insert (address.begin () + i + 2, ']');
			i += 2;
		}
	}
	return address;
}

用到了insert函数： 插入单个字符：

iterator insert (const_iterator p, char c);

插入多个字符：

string& insert (size_t pos, size_t n, char c);

iterator insert (const_iterator p, size_t n, char c);

方法二：重新构建一个string

string defangIPaddr(string address) 
    {
        string s="";
        string a="[.]";
        
        for(int i=0;i<address.length();i++)
        {
            if(address[i]=='.')
                s=s+a;
            else
            s=s+address[i];
        }
        
        return s;
    }

用到了string的“+”运算符。