行程编码（atoi函数）

#include<iostream>
#include<string>
#include<vector>
using namespace std;
void jiema(string s)
{
    cout << "解码之后为：" << endl;
    for(int i = 0; i < s.size(); i++)
    {
        if(s[i + 1] == '*')
        {
            int j = i + 1;
            int len = 0;
            while(s[j + 1] >= 48 && s[j + 1] <= 57)
            {
                len++;
                j = j + 1;
            }
            string temp = s.substr(i + 2, len);
            int num = atoi(temp.c_str());
            for(int k = 0; k < num; k++)
            {
                cout << s[i];
            }
            i = j;
        }
        else
        {
            cout << s[i];

        }
    }
}

void bianma(string s)
{
    vector<char>A;
    int p = 1;
    int j = 0;
    for(; j < s.size();)
    {
        while(s[j] == s[j + 1] && j < s.size())
        {
            p++;
            j = j + 1;
        }
        if(p >= 4)
        {
            A.push_back(s[j]);
            A.push_back('*');
            A.push_back(p);
            p = 1;
            j = j + 1;
        }
        else if(p < 4)
        {
            for(int k = 0; k < p; k++)
            {
                A.push_back(s[j]);
            }
            p = 1;
            j = j + 1;
        }
    }
    cout << "编码之后为：" << endl;
    for(int b = 0; b < A.size(); b++)
    {
        if(A[b] >= 0 && A[b] <= 9)
            cout << int(A[b]);
        else
            cout << A[b];
    }
    cout << endl;
    cout << "压缩比为：" << endl;
    double y = double(A.size()) / s.size();
    cout << y << endl;
}
void main()
{
    cout << "请输入代码：①代码中含有数字表示需要解码解压缩②代码中不含数字表示需要编码压缩" << endl;
    string s;
    for(; cin >> s;)
    {
        int i = 0;
        for(; i < s.size(); i++)
        {
            if(s[i] >= 48 && s[i] <= 57) //解码
            {
                jiema(s);
                break;
            }
        }
        if(i == s.size())
        {
            bianma(s);
        }
    }
}