13. Roman to Integer

int romanToInt(char* s)
{
    int I = 1;
    int V = 5;
    int X = 10;
    int L = 50;
    int C = 100;
    int D = 500;
    int M = 1000;
    int result = 0;
    int index = 0;
    int buff[20];
    int i = 0;
    int temp = 0;
    while(s[index] != '\0')
    {
        switch (s[index])
        {
        case 'I':buff[index] = I;
            break;
        case 'V':buff[index] = V;
            break;
        case 'X':buff[index] = X;
            break;
        case 'L':buff[index] = L;
            break;
        case 'C':buff[index] = C;
            break;
        case 'D':buff[index] = D;
            break;
        case 'M':buff[index] = M;
            break;
        }
        index++;
    }

//    for(i = 0;i < index;i++)
//    {
//        printf("%d",buff[i]);
//    }
//    printf("\nindex = %d",index);
    i = 0;
    if(index == 1)
    {
        return result = buff[i];
    }
    while(i < index)
    {
        if(buff[i] < buff[i+1])
        {
            temp=buff[i+1] - buff[i];
            i++;
        }
        else if(buff[i] == buff[i+1])
        {
            temp = buff[i] + buff[i+1];
            i++;
        }
        else
        {
            temp = buff[i];
        }
        i++;
        result = result + temp;
        if(i == (index - 1))
        {
            result = result + buff[i];
            break;
        }
    }
    return result;
}

反思：
1 因为我是用数组做的，所以在运行过程中一定要注意会不会出现数组的范围不够，或者是出现下标越界。我一开始提交的代码中没有下面这几行语句

    if(index == 1)
    {
        return result = buff[i];
    }

这样就会造成数组下标越界。