如何在字符串对象中输入？ [英] How to take input in a string object?

问题描述

我的代码没有在字符串对象s1中输入。我写了一个程序，用链接列表存储学生的信息。如何根据学生姓名按字母顺序对列表进行排序？

My code is not taking input in string object s1. I wrote a program that stores information of students using linked list. How do I sort the list in alphabetical order according to student name?

#include<iostream>
#include<iomanip>
#include<string>
using namespace std;

struct node
{
       int roll;
       int link;
       int score;
       string name;
};
void traverse();
//void search();
void insert();
//void del();
node abc[50];
int start = -1;
int avail = 0;
main()
{
      int choice;
      for(int i=0; i<49; i++)
      abc[i].link = i+1;
      abc[49].link = -1;
      do
      {
      cout<<"\nPress\n1. Insertion\n2. Traversing\n3. Searching\n4. Delete:  ";
      cin>>choice;
      switch(choice)
      {
                    case 1: insert(); break;
                    case 2: traverse(); break;
                    //case 3: search(); break;
                    //case 4: del(); break;
                    default: cout<<"\nInvalid Input"<<endl;
                    
      }
      }while(1);
      system("pause");
}
void insert()
{
     int item1, item2; string s1;
     if(avail == -1)
     {
              cout<<"Overflow!"<<endl;
              return;
     }
     cout<<"Enter Roll Number: "; cin>>item1;
     cout<<"Enter Score: "; cin>>item2;
     cout<<"Enter student name: "; getline(cin, s1);
     
     //insertion at the beginning
     
     if(start == -1 || s1<abc[start].name)
     {
              int newnode = avail;
              avail = abc[avail].link;
              abc[newnode].roll = item1;
              abc[newnode].score = item2;
              abc[newnode].name = s1;
              abc[newnode].link = start;
              start = newnode;
              return;
     }
     
     //insertion somewhere in the mid
     
     int prev = start;
     for(int i = abc[start].link; i!=-1; i = abc[i].link)
     {
             if(s1<abc[i].name)
             {
                  int newnode = avail;
                  avail = abc[avail].link;
                  abc[newnode].roll = item1;
                  abc[newnode].score = item2;
                  abc[newnode].name = s1;
                  abc[newnode].link = i;
                  abc[prev].link = newnode;
                  return;
             }
             else
             prev = i;
     }
     
     //insertion at the end
     
     int newnode= avail;
     avail = abc[avail].link;
     abc[newnode].roll = item1;
     abc[newnode].score = item2;
     abc[newnode].name = s1;
     abc[newnode].link = -1;
     abc[prev].link = newnode;
     return;
}
void traverse()
{
     if(start ==-1)
     {
              cout<<"\nList Empty"<<endl;
              return;
     }
     cout<<"Student Name"<<setw(20)<<"Roll No."<<setw(20)<<"Score\n";
     for(int i = start; i!=-1; i=abc[i].link)
     {
             cout<<setw(12)<<abc[i].name;
             cout<<setw(20)<<abc[i].roll;
             cout<<setw(20)<<abc[i].score;
             cout<<"\n";
     }
     
}

推荐答案

您可能会使用（至少两种）方法：

You might use (at least two) approaches:

1. Homework 一：选择你最喜欢的排序算法，并实现它（这应该非常简单，可能只需要实现两项的交换操作列表）。
2. 实用一：使用 C ++ 标准库： std :: list 和 std :: sort 应该可以让您快速提供所需的代码。

1. Homework one: pick your favourite sorting algorithm, and implement it (this should be pretty straightforward, possibly requiring just to implement the swap operation for two items of the list).
2. Practical one: use the C++ standard library: std::list and std::sort should allow you to quickly provide the required code.

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