[itint5]Excel数转换

//将十进制数转换为excel数
string decToExcel(int decNum) {
    string ans;
    while (decNum != 0) {
        char c = (char) ((decNum - 1) % 26 + ‘A‘);
        decNum = (decNum - 1) / 26;
        ans += c;
    }
    int len = ans.length();
    for (int i = 0; i < len/ 2; i++) {
        char tmp = ans[i];
        ans[i] = ans[len - i - 1];
        ans[len - i - 1] = tmp;
    }
    return ans;
}
//将excel数转换为十进制数
int excelToDec(string excelNum) {
    int num = 0;
    for (int i = 0; i < excelNum.length(); i++) {
        num = num * 26 + excelNum[i] - ‘A‘ + 1;
    }
    return num;
}