OJ系统读入数据流的方法总结C++

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样例输入：

3,1,2

1,2,3,4,5

345,2324,11,2,4,0,9

对于这样的输入，应该先采用getline()函数获得一行数据，然后将这个字符串中数字取出。从字符串转换为int或者其他类型有三种方式。

方法一，纯正C++风格

#include <iostream>#include <vector>#include <string>#include <sstream>using namespace std;int main(){    string line;    vector<string> str_list;    double num[20] = {0.0};    int length = 0;    getline(cin,line);    int index = 0;    string str_temp = "";    while(true)    {        index = line.find(",");        if(-1 == index)        {            str_temp = line.substr(0,line.length());            str_list.push_back(str_temp);            break;        }        str_temp = line.substr(0,index);        str_list.push_back(str_temp);        line.erase(0,index+1);    }        vector<string>::iterator iter;    for(iter=str_list.begin(); iter<str_list.end(); iter++)    {        cout<<*iter<<endl;        istringstream double_temp(*iter);        double_temp>>num[length++];    }    cout<<endl<<"double"<<endl;    for(int i=0;i<length;i++)        cout<<num[i]<<endl;            return 0;}

方法二，半C半C++风格

#include <sstream>#include <string>#include <iostream>using namespace std;int main(){    string line;    double num[20]={0.0};    int length=0;    getline(cin, line);    const char *d = " ,";    char * p;    p = strtok(const_cast<char *>(line.c_str()),d);   //分割字符串标记    while(p)    {        cout<<p<<endl;        istringstream temp(p);     //必须包含头文件cstream,将一个string转为数据流        temp>>num[length++];       //此方法对float和double都是合适的，对应的num[20]数组应该声明为float或double类型        p=strtok(NULL,d);    }    cout<<"The num list:"<<endl;    for(int i=0;i<length;i++)        cout<<num[i]<<endl;    return 0;}

方法三，半C半C++风格

#include <cstring>#include <string>#include <iostream>#include <cstdlib>using namespace std;int main(){    int i, count=0;    string line;    double num[20]={0};    int length=0;    getline(cin, line);    const char *d = " ,";    char * p;    p = strtok(const_cast<char *>(line.c_str()),d);    while(p)    {        cout<<p<<endl;        num[length++] = atof(p);        p=strtok(NULL,d);    }    cout<<"The num list:"<<endl;    for(int i=0;i<length;i++)        cout<<num[i]<<endl;    return 0;}

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