[英]Merging Two Text Files Sorted
I need to merge two text files and have them sort by "lastName" on a third outputted file. 我需要合并两个文本文件,并在第三个输出文件上按“ lastName”对它们进行排序。 My code is below, it is outputting gibberish, all on one line. 我的代码在下面,它输出乱码,全部在一行上。 I understand my overload may be stupid, any help is appreciated. 我了解我的超载可能是愚蠢的,我们将不胜感激。
//header
#include <fstream>
#include <string>
#include <iostream>
using namespace std;
struct mergedList {
string firstName;
string lastName;
float gpa;
int hours;
};
ostream& operator << (ostream& os, mergedList A) {
os << A.firstName << "\t" << A.lastName << "\t" << A.gpa << "\t" << A.hours;
return os;
}
istream& operator >> (istream& is, mergedList& A) {
is >> A.firstName >> A.lastName >> A.gpa >> A.hours;
return is;
}
void swap(mergedList D1[], int i, int j);
void sort(mergedList D1[], int size);
int main() {
ifstream indata;
ifstream indata2;
ofstream outdata;
indata.open("merge1.txt");
indata2.open("merge2.txt");
outdata.open("merged.txt");
//begin sentinel controlled loop for both lists
mergedList D1[100];
int index = 0;
indata >> D1[index];
while (!indata.eof()) {
index++;
indata >> D1[index];
}
sort(D1, index);
mergedList D2[100];
int index2 = 0;
indata2 >> D2[index2];
while (!indata2.eof()) {
index2++;
indata2 >> D2[index2];
}
sort(D2, index); {
int i = 0, j = 0;
while ((i < index) && (j < index2)) if (D1[i].lastName < D2[j].lastName) {
outdata << D1[i];
i++;
indata >> D1[i];
} else {
outdata << D2[j];
j++;
indata2 >> D2[j];
}
}
indata.close();
indata2.close();
outdata.close();
return 0;
}
void swap(mergedList D1[], int i, int j) {
mergedList temp;
temp = D1[i];
D1[i] = D1[j];
D1[j] = temp;
return;
}
void sort(mergedList D1[], int size) {
for (int p = 1; p < size; p++) {
for (int c = 0; c < size - p; c++) {
if (D1[c].lastName > D1[c + 1].lastName) swap(D1, c, c + 1);
}
}
return;
}
If optimization is an issue for you, I suggest you use STL containers as the proper sort methods are implemented. 如果优化对您来说是一个问题,建议您使用STL容器,因为已实现了正确的排序方法。 Do not use static arrays if your code should work on every given input file. 如果您的代码应在每个给定的输入文件上工作,请不要使用静态数组。 I might also add that you can first merge the two files and then sort the third one. 我可能还要补充一点,您可以先合并两个文件,然后对第三个文件进行排序。
Here is some code. 这是一些代码。 I have tried to explain as much as I can. 我已经尽力解释了。 If you are using C++ you should try to take advantage of the containers and algorithms that are already available for you. 如果您使用的是C ++,则应尝试利用已经为您提供的容器和算法 。
struct mergedList
{
string firstName;
string lastName;
float gpa;
int hours;
};
ostream& operator <<(ostream& os, mergedList A)
{
os << A.firstName << "\t" << A.lastName << "\t" << A.gpa << "\t" << A.hours;
return os;
}
istream& operator >>(istream& is, mergedList& A)
{
is >> A.firstName >> A.lastName >> A.gpa >> A.hours;
return is;
}
// We use this to compare two MergedList structs. i.e. by first name
// http://www.cplusplus.com/reference/algorithm/sort/ for an example
struct my_sorter {
bool operator() (mergedList one, mergedList two) { return one.firstName < two.firstName ; }
};
int main()
{
ifstream indata;
ifstream indata2;
ofstream outdata;
indata.open("merged.txt");
indata2.open("merged2.txt");
outdata.open("merged.txt");
// This can be a vector. No need for array here.
vector<mergedList> D1;
int index=0, index2 = 0;
mergedList tmp;
// You can read from streams like this if the data is formatted.
while (indata >> tmp)
{
D1.push_back(tmp);
index++; // Maybe you need this??
}
// Read the second file in to the same vector.
// You don't need another one.
while (indata2 >> tmp)
{
D1.push_back(tmp);
index2++;
}
cout << "Before sorting" << endl;
copy(D1.begin(), D1.end(), ostream_iterator<mergedList>(cout, "\n"));
// Sort the vector using the std::sort algorithm.
// http://www.cplusplus.com/reference/algorithm/sort/ for an example
sort(D1.begin(), D1.end(), my_sorter());
cout << "After sorting" << endl;
copy(D1.begin(), D1.end(), ostream_iterator<mergedList>(cout, "\n"));
// Write the sorted list to the output file
copy(D1.begin(), D1.end(), ostream_iterator<mergedList>(outdata, "\n"));
indata.close();
indata2.close();
outdata.close();
return 0;
}
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