原创 使用序列式容器并分析字符串.cpp

#include "Student_info.h"
#include "grade.h"
#include <vector>
#include <list>

using std::string;
using std::vector;

// predicate to determine whether a student failed
bool fgrade(const Student_info& s)
{
 return grade(s) < 60;
}

// version 3:iterators but no indexing: still potentially slow
vector<Student_info> extract_fails(vector<Student_info>& students)
{
 vector<Student_info> fail;
 vector<Student_info>::iterator iter = students.begin();
 while (iter != students.end()) {
   if (fgrade(*iter)) {
    fail.push_back(*iter);
    iter = students.erase(iter);
   }
   else
    ++ iter;
 }
 return fail;
}
////////////////////////////////////////////////////////////////

#include "Student_info.h"
#include "grade.h"
#include <vector>
#include <list>

using std::string;
using std::list;

// predicate to determine whether a student failed
bool fgrade(const Student_info& s)
{
 return grade(s) < 60;
}

// version 4: use list instead of vector
list<Student_info> extract_fails(list<Student_info>& students)
{
 list<Student_info> fail;
 list<Student_info>::iterator iter = students.begin();
 while (iter != students.end()) {
   if (fgrade(*iter)) {
    fail.push_back(*iter);
    iter = students.erase(iter);
   }
   else
    ++ iter;
 }
 return fail;
}

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