C++ 数组选择排序问题和输出
你好,我不确定我的代码出了什么问题。 选择排序可以工作,但当程序再次要求用户输入姓名时,他们找不到正确的人。有人能帮我吗?我不确定出了什么问题 编辑:我现在第二次请求输入时遇到的错误是“找不到名称”。我不明白为什么 图片如下: 这是我的完整代码:C++ 数组选择排序问题和输出,c++,arrays,binary-search,selection-sort,linear-search,C++,Arrays,Binary Search,Selection Sort,Linear Search,你好,我不确定我的代码出了什么问题。 选择排序可以工作,但当程序再次要求用户输入姓名时,他们找不到正确的人。有人能帮我吗?我不确定出了什么问题 编辑:我现在第二次请求输入时遇到的错误是“找不到名称”。我不明白为什么 图片如下: 这是我的完整代码: #include <iomanip> #include <string> #include <iostream> #include <fstream> using namespace std; //
#include <iomanip>
#include <string>
#include <iostream>
#include <fstream>
using namespace std;
// GLOBAL CONSTANTS
const int NUM_NAMES = 20;
// FUNCTION PROTOTYPES
void getNames(ifstream &, string[], int[], int);
int linearSearch(const string[], int, string);
int binarySearch(const string[], int, string);
void selectionSort(string[], int[], int);
void displayData(const string[], const int[], int);
void displaySearch(const string[], const int[], int);
int main()
{
// LOCAL VARIABLES
string names [NUM_NAMES];
int marks [NUM_NAMES];
ifstream inStream; // Input file stream variable
int index = 0;
string searchWho;
// FUNCTION CALL 1
getNames (inStream, names, marks, NUM_NAMES);
cout << endl;
cout << " Students and Marks:" << endl;
cout << " ______________________________" << endl << endl;
// FUNCTION CALL 2: DisplayData
displayData(names, marks, NUM_NAMES);
// OUTPUT - Perform search - USER INPUT
cout << endl;
cout << " Please enter the first and last name of who who want to look up, seperated with a space." << endl << endl;
cout << " "; cin >> searchWho;
cout << endl << endl;
// FUNCTION CALL 3: linearSearch
index = linearSearch (names, NUM_NAMES, searchWho);
// FUNCTION CALL 4: displaySearch
displaySearch(names, marks, index);
// FUNCTION CALL 5: selectionSort
selectionSort (names, marks, NUM_NAMES);
cout << endl;
cout << " Students and Marks:" << endl;
cout << " ______________________________" << endl << endl;
displayData(names, marks, NUM_NAMES);
// OUTPUT - Perform search - USER INPUT
cout << endl;
cout << " Please enter the first and last name of who who want to look up, seperated with a space." << endl << endl;
cout << " "; cin >> searchWho;
cout << endl << endl;
// FUNCTION CALL 4
index = binarySearch (names, NUM_NAMES, searchWho);
displaySearch(names, marks, index);
cout << " "; return 0;
}
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// FUNCTION 1: getNames
// DESCRIPTION: Function opens data file students.txt
// Function reads data from students.txt and stores data
// appropriately according to customerCode and utilityCharge
// in parallel arrays Customer[] and Charge[]
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
void getNames (ifstream &inStream, string names[], int marks[], int numElts)
{
// Open input file
inStream.open ("students.txt");
string studentNames; // Student names - Last name followed by first
int studentMarks = 0; // Student mark for text/exam
// Read in data from students.txt
while (!inStream.eof())
{
for(int count = 0; count < numElts; count ++)
{
inStream >> names[count];
inStream >> marks[count];
}
}
inStream.close();
}
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// FUNCTION: LinearSearch
// DESCRIPTION:
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
int linearSearch (const string names[], int numElts, string who)
{
int index = 0; // Used as a subscript to search array
int position = -1; // To record position of search value
bool found = false; // Flag to indicate if value was found
while (index < numElts && !found)
{
if (names[index] == who) // If the name is found
{
found = true; // Set the flag
position = index; // Record the value's subscript
}
index++; // Go to the next element
}
return position; // Return the position, or -1
}
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// FUNCTION: SelectionSort
// DESCRIPTION:
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
void selectionSort(string names[], int marks[], int numElts)
{
int startScan;
int minIndex;
int startName;
for (startScan = 0; startScan < (numElts - 1); startScan++)
{
startName = startScan;
for (int minIndex = startScan + 1; minIndex < numElts; minIndex++)
{
if (names[minIndex] > names[startName])
{
startName = minIndex;
string tempString = names[startScan];
names[startScan] = names[minIndex];
names[minIndex] = tempString;
// Aligning arrays
int tempInt = marks[startScan];
marks[startScan] = marks[minIndex];
marks[minIndex] = tempInt;
}
}
}
}
int binarySearch(const string names[], int numElts, string who)
{
int first = 0; // First array element
int last = numElts - 1; // Last array element
int middle; // Mid point of search
int position = -1; // Position of search value
bool found = false; // Flag
while (!found && first <= last)
{
middle = (first + last) / 2; // Calculate mid point
if (names[middle] == who) // If value is found at mid
{
found = true;
position = middle;
}
else if (names[middle] > who) // If value is in lower half
{
last = middle - 1;
}
else
{
first = middle + 1; // If value is in upper half
}
}
return position;
}
void displayData(const string names[], const int marks[], int numElts)
{
// OUTPUT
for (int count = 0; count < numElts; count++)
{
cout << " " << left << setw(15) << names[count] << right << setw(15) << marks[count] << endl;
}
}
void displaySearch(const string names[], const int marks[], int index)
{
if (index == -1)
{
cout << " Name not found. Restart the program to search again." << endl << endl;
}
else
{
cout << names[index] << " scored " << marks[index] << " marks." << endl << endl;
}
}
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使用名称空间std;
//全局常数
const int NUM_NAMES=20;
//功能原型
void getNames(ifstream&,string[],int[],int);
int linearSearch(常量字符串[],int,字符串);
int二进制搜索(常量字符串[],int,字符串);
void selectionSort(字符串[],整数[],整数);
void displayData(常量字符串[],常量整数[],整数);
void displaySearch(常量字符串[],常量整数[],整数);
int main()
{
//局部变量
字符串名[NUM_names];
整数标记[NUM_name];
ifstream inStream;//输入文件流变量
int指数=0;
字符串搜索谁;
//函数调用1
getNames(流内、名称、标记、NUM_名称);
cout从共享图像中,数组没有正确排序。例如
艾利森,杰夫45
柯林斯,比尔80
艾伦,吉姆82
如以下代码所示:
if (names[minIndex] > names[startName])
{
startName = minIndex;
//...
}
startName
表示names
数组中最大名称的索引,不是吗?(数组是按降序排序的,对吗?)
因此,假设将索引startName
处的最大名称与索引startScan
处的当前扫描名称进行交换
startName = startScan;
for (int minIndex = startScan + 1; minIndex < numElts; minIndex++)
{
if (names[minIndex] > names[startName])
{
startName = minIndex;
}
}
string tempString = names[startScan];
names[startScan] = names[startName];
names[startName] = tempString;
// Aligning arrays
int tempInt = marks[startScan];
marks[startScan] = marks[startName];
marks[startName] = tempInt;
到
if(名称[minIndex]
您可以添加几行“students.txt”文件吗?
if (names[minIndex] > names[startName])
{
startName = minIndex;
}
if (names[minIndex] < names[startName])
{
startName = minIndex;
}