明天看stringstream主要是相当与sprintf／sscanf函数的作用

来源：互联网发布：淘宝种子新规编辑：程序博客网时间：2024/05/18 10:46

C_Style

#include<iostream>#include<cstdio>#include<cstring>using namespace std;int get_next(int x){    char s[10];    sprintf(s, "%d", x);    int n = strlen(s);    for(int i = 0; i < n; ++i)        for(int j = i+1; j < n; ++j)            if(s[i] > s[j])            {                char t = s[i];                s[i] = s[j];                s[j] = t;            }    int b;    sscanf(s, "%d", &b);//字符串反转    for(int i = 0; i < n/2; ++i)    {        char t = s[i];        s[i] = s[n-i-1];        s[n-i-1] = t;    }    int a;    sscanf(s, "%d", &a);    return a-b;}int num[2000], count;int main(){    cin >> num[0];    cout << num[0];    count = 1;    while(1)    {        //生成并输出下一个数        num[count] = get_next(num[count-1]);        cout << " -> " << num[count];        //在数组n中寻找新生成的书        int found = 0;        for(int i = 0; i < count; ++i)            if(num[i] == num[count])            {                found = 1;                break;            }//如果找到，推出循环        if(found)break;        count++;    }    cout << endl;    return 0;}

C++_Style

#include<iostream>#include<sstream>using namespace std; int get_next(int x){    stringstream stream;    string s;    stream << x;    stream >> s;    for(string::size_type i  = 0; i != s.size(); ++i)        for(string::size_type j = i + 1; j != s.size(); ++j)            if(s[i] > s[j])            {                char t = s[i];                s[i] = s[j];                s[j] = t;            }    stream.clear();//多次转换前，必须清楚stream    stream << s;    stream >> x;//字符串反串    for(string::size_type i = 0; i < s.size()/2; ++i)    {        char t = s[i];        s[i] = s[s.size()-i-1];        s[s.size()-i-1] = t;    }    int y;    stream.clear();//多次转换前，必须清楚stream    stream << s;    stream >> y;    return y - x;}int num[2000], count;int main(){    cin >> num[0];    cout << num[0];    count = 1;    while(1)    {//生成并输出下一个数        num[count] = get_next(num[count-1]);        cout << " -> " << num[count];//在数组n中寻找新生成的数        int found = 0;        for(int i  = 0; i < count; ++i)            if(num[i] == num[count])            {                found = 1;                break;            }        if(found) break;        count++;    }    cout << endl;    return 0;}