1078 字符串压缩与解压

题目链接：https://pintia.cn/problem-sets/994805260223102976/problems/994805262018265088

题解：

#include <iostream>
#include<cstdio>//getchar所需的头文件
#include<string>
using namespace std;

int main() {
    char select;
    cin >> select;
    getchar();//读入回车键
    string str;
    getline(cin, str);
    if (select == 'C') {
        int sum = 0;
        for (int i = 0; i < str.size(); i++) {
            if (str[i + 1] == str[i]) sum++;
            else {
                if (sum == 0) cout << str[i];
                else {
                    cout << sum + 1 << str[i];
                }
                sum = 0;
            }
        }
    }
    else {
        for (int i = 0; i < str.size(); i++) {
            int sum = 0;
            while (1) {
                if (str[i] >= '0'&&str[i] <= '9')
                    sum = sum * 10 + str[i++] - '0';//单个字符的个数可能不是一位数
                else break;
            }
            if (sum == 0) cout << str[i];
            for (int j = 0; j < sum; j++) {
                cout << str[i];
            }
        }
    }
    return 0;
}