012 Integer to Roman 整数转换成罗马数字

class Solution {
public:
    string intToRoman(int num) {
        string res = "";
		char roman[] = { 'M', 'D', 'C', 'L', 'X', 'V', 'I' };
		int value[] = { 1000, 500, 100, 50, 10, 5, 1 };

		for (int n = 0; n < 7; n += 2) 
        {
			int x = num / value[n];
            if(x<4)
            {
                for(int i=1;i<=x;++i)
                {
                    res+=roman[n];
                }
            }
            else if(x==4)
            {
                res=res+roman[n]+roman[n-1];
            }
            else if(x>4&&x<9)
            {
                res+=roman[n-1];
                for(int i=6;i<=x;++i)
                {
                    res+=roman[n];
                }
            }
			else if (x == 9)
            {
                res=res+roman[n]+roman[n-2];
            }
            num%=value[n];
		}
		return res;
    }
};