POJ 1051 P,MTHBGWB

1. C++中string类的练习，使用的数据结构慢慢地开始有心得了；

2. string类中的+=操作符和append( )函数的使用；

3. 这道题很简单，开始出错是因为string类型的变量没有初始化。string str = "";//初始化为空字符串；

4. 推荐一个c++的网站（cplusplus.com - The C++ Resources Network）。

#include <iostream>
#include <string>
#include <cstring>
using namespace std;
struct type
{
    string str;
    char let;
    int len;
}ltr[30]={{".-",'A',2},{"-...",'B',4},{"-.-.",'C',4},{"-..",'D',3},{".",'E',1},{"..-.",'F',4},{"--.",'G',3},{"....",'H',4},{"..",'I',2},{".---",'J',4},{"-.-",'K',3},{".-..",'L',4},{"--",'M',2},{"-.",'N',2},{"---",'O',3},{".--.",'P',4},{"--.-",'Q',4},{".-.",'R',3},{"...",'S',3},{"-",'T',1},{"..-",'U',3},{"...-",'V',4},{".--",'W',3},{"-..-",'X',4},{"-.--",'Y',4},{"--..",'Z',4},{"..--",'_',4},{".-.-",',',4},{"---.",'.',4},{"----",'?',4}};

int main()
{
    string str_in, tmp, str_out, tmp_m;
    int num[101], i, k, mm, nn, cas, j;
    cin >> cas;
    for (i = 1; i <= cas; i++)
    {
        str_in = "";
        cin >> str_in;
        memset(num, 0, sizeof(num));
        str_out = "";
        tmp = "";
        for (j = 0; j < str_in.length(); j++)
            for (k = 0; k < 30; k++)
                if (str_in[j] == ltr[k].let)
                {
                    tmp += ltr[k].str;
                    num[j] = ltr[k].len;
                    break;
                }
//        cout << tmp << endl;
//        for (j = 0; j < str_in.length(); j++)
//            cout << num[j];
//        cout << endl;
        mm = num[str_in.length() - 1];
        nn = 0;
        for (j = str_in.length() - 1; j >= 0; j--)
        {
            tmp_m = "";
            for (k = nn; k < mm; k++)
                tmp_m += tmp[k];
//            cout << tmp_m << endl;
            for (k = 0; k < 30; k++)
                if (tmp_m == ltr[k].str)
                {
                    str_out += ltr[k].let;
                    break;
                }
            nn += num[j];
            mm += num[j-1];
        }
        cout << i << ": " << str_out << endl;
    }
    return 0;
}