所以问题是，我正在取一个示例文件作为输入，要求输入用户帐号。现在，输出是:
What is the filename of account numbers? sample.txt
What is the account number you are looking for? 5552012
-858993460
4520125
5658845
7895122
8451277
1302850
8080152
4562555
5552012
5050552
7825877
1250255
1005231
6545231
3852085
7576651
7881200
4581002
The account number you were looking for is: 1
Press any key to continue . . .
下面输出的数字:"What is The account number?"是由于调试目的的'for'循环。输出的问题还在于顶部数字(-858993460)不是sample.txt文件中存在的数字。应该是5658845。我猜负数是最小的整数。
这部分是我正在使用的代码。看起来冒泡排序算法并不是很正确。但是，按照指示，我们要按照书上的例子来做，我就是这么做的。我已经检查了算法功能几次，没有发现错误，但我的评估可能是错误的。这个问题导致了一个更大的问题，即阻止在排序数组中找到正确的帐号，在其当前状态下返回1，这不是一个存在的数字。
#include <stdafx.h>
#include <stdio.h>
#include <fstream>
#include <string>
#include <algorithm>
#include <iostream>
using namespace std;
//prototypes
void sortAcctNums(int accounts[], int arraySize);
bool findAcctNum(int accounts[], int numElems, int accountNumSearched);
//main part of the program. This is where all the magic happens
int main(){
string fileName;
int accountNumSearched, count = 0;
const int arraySize = 18;
int accounts[arraySize];
int location;
fstream inputFile(fileName, ios::in);
cout << "What is the filename of account numbers? ";
cin >> fileName;
inputFile.open(fileName);
if (inputFile.is_open()){//makes sure the file is able to be read, if not then requests user to try again
cout << "What is the account number you are looking for? ";
cin >> accountNumSearched;
while (inputFile >> accounts[count]){
count++;//populates the array
}
inputFile.close();//closes the file stream
sortAcctNums(accounts, arraySize);//sorts the account numbers
location = findAcctNum(accounts, arraySize, accountNumSearched);//assigns the value of the fundAcctNum function to location
if (location == -1){
cout << "The account number could not be found" << endl;
exit;
}
else
cout << "The account number you were looking for is: " << location << endl;
}
else
cout << "Error opening file. Please try again. " << endl;
return 0;
}
//this function sorts the account numbers with a bubble sort algorithm
void sortAcctNums(int accounts[], int arraySize){
bool swap;
int temp;
do{
swap = false;
for (int i = 0; i < (arraySize - 1); i++){
if (accounts[i] > accounts[arraySize + 1]){
temp = accounts[i];
accounts[i] = accounts[arraySize + 1];
accounts[arraySize + 1] = temp;
swap = true;
}
}
} while (swap);
//this loop is only for testing purposes and should be removed during final build
for (int i = 0; i < arraySize; i++){
cout << accounts[i] << endl;
}
}
//This function searches the sorted array for the specified account number with a Binary sort algorithm
bool findAcctNum(int accounts[], int numElems, int accountNumSearched){
int first = 0,
last = numElems - 1,
middle,
position = -1;
bool found = false;
while (!found && first <= last){
middle = (first + last) / 2;
if (accounts[middle] == accountNumSearched){
found = true;
position = middle;
}
else if (accounts[middle] > accountNumSearched)
last = middle - 1;
else
first = middle + 1;
}
return position;
}//end search
您的冒泡排序根本不正确。你有:
do{
swap = false;
for (int i = 0; i < (arraySize - 1); i++){
if (accounts[i] > accounts[arraySize + 1]){
temp = accounts[i];
accounts[i] = accounts[arraySize + 1];
accounts[arraySize + 1] = temp;
swap = true;
}
}
} while (swap);
这不是冒泡排序。对于冒泡排序，您需要嵌套的for循环。回到您的示例，并确保您完全实现了它。一个典型的冒泡排序看起来像这样:
swap = true;
for (int i = 0; i < (arraySize - 1) && swap; ++i)
{
swap = false;
for (int j = 0; j < (arraySize - i - 1); ++j)
{
if (array[j] > array[j+1])
{
temp = array[j];
array[j] = array[j+1];
array[j+1] = temp;
swap = true;
}
}
}
你在数组中得到假数字的原因是因为你将当前项目(accounts[i])与accounts[arraySize+1]进行比较。在这种情况下，您将与accounts[20]进行比较。由于数组中只有18个元素，因此您将与存储在数组末尾的内存中的某个随机值进行比较。
正确的程序是:
#include <stdafx.h>
#include <stdio.h>
#include <fstream>
#include <string>
#include <algorithm>
#include <iostream>
using namespace std;
//prototypes
void sortAcctNums(int accounts[], size_t count);
int findAcctNum(int accounts[], int numElems, int accountNumSearched);
//main part of the program. This is where all the magic happens
int main(){
string fileName;
int accountNumSearched, count = 0;
const int arraySize = 18;
int accounts[arraySize];
int location;
fstream inputFile(fileName, ios::in);
cout << "What is the filename of account numbers? ";
cin >> fileName;
inputFile.open(fileName);
if (inputFile.is_open()){//makes sure the file is able to be read, if not then requests user to try again
cout << "What is the account number you are looking for? ";
cin >> accountNumSearched;
while (inputFile >> accounts[count]){
count++;//populates the array
}
inputFile.close();//closes the file stream
sortAcctNums(accounts, sizeof(accounts)/sizeof(*accounts));//sorts the account numbers
location = findAcctNum(accounts, count, accountNumSearched);//assigns the value of the fundAcctNum function to location
if (location == -1){
cout << "The account number could not be found" << endl;
exit;
}
else
cout << "The account number you were looking for is: " << accounts[location] << endl
}
else
cout << "Error opening file. Please try again. " << endl;
return 0;
}
//this function sorts the account numbers with a bubble sort algorithm
void sortAcctNums(int accounts[], size_t count){
bool swap = true;
int temp;
while (count-- && swap){
swap = false;
for (size_t i = 0; i < count; ++i){
if (accounts[i] > accounts[i + 1]){
std::iter_swap(accounts + i, accounts + i + 1);
swap = true;
}
}
}
}
//This function searches the sorted array for the specified account number with a Binary search algorithm
int findAcctNum(int accounts[], int numElems, int accountNumSearched){
int first = 0,
last = numElems - 1,
middle,
position = -1;
bool found = false;
while (!found && first <= last){
middle = (first + last) / 2;
if (accounts[middle] == accountNumSearched){
found = true;
position = middle;
}
else if (accounts[middle] > accountNumSearched)
last = middle - 1;
else
first = middle + 1;
}
return position;
}//end search
冒泡排序应该是这样的:
for (int i = 0 ; i < (arraySize - 1); i++) {
for (int j = 0 ; j < arraySize - i - 1; j++) {
if (array[j] > array[j+1]) {
int swap = array[j];
array[j] = array[j+1];
array[j+1] = swap;
}
}
}
试一试，看看你是否仍然得到不好的结果。