C++ insertion sort from a txt file - c++

Question

I have to read from a .txt file and out it with a different .txt file. I have to use insertion sort in order to sort them based on two numbers. I could only get this far, I don't know how to do insertion sort in this program where I have two numbers to sort to.
Here is my code:
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main(void)
{
int serialno[100], suratno[100], ayatno[100];
string order;
string str;
char ch;
int i = 0;
int j, temp;
ifstream fin;
fin.open("text.txt");
if(!fin)
{
cout << "Cannot open file \'text.txt\'! Quitting.\n";
exit(0);
}
while(fin)
{
fin.get(ch); //gets .
getline(fin, order, '('); //allegedly it removes the delimiter char from stream too
fin >> suratno;
fin.get(ch); //gets :
fin >> ayatno;
fin.get(ch); //gets )
fin.get(ch); //gets \n
cout << serialno << "." << order << "("<<suratno<<":<<ayatno<<")\n";
}
fin.close();
//sort algorithm
for (int i = 0; i < length; i++){
j = i;
while (j > 0 && suratno [j] < suratno [j-1]){
temp = suratno [j];
suratno [j] = suratno [j-1];
suratno [j-1] = temp;
j--;
cout << serialno << endl;
}
}
}
ofstream fout;
fout.open("newtext.txt");
if(!fout)
{
cout << "Cannot open output file\'orderedquranorders.txt\'!Quitting.\n";
exit(0);
}
i = 0;
//write sorted list to output file
fout.close();
cout << i << " orders successfully sorted and written.\n";
}
this is the text file (numbers in bracket should be used, firstly with number before colon, and secondly with number after colon):
1. Do not be rude in speech (3:159)
2. Restrain Anger (3:134)
3. Be good to others (4:36)
4. Do not be arrogant (7:13)
5. Forgive others for their mistakes (7:199)
6. Speak to people mildly (20:44)
7. Lower your voice (31:19)
8. Do not ridicule others (49:11)
9. Be dutiful to parents(17:23)
current output:
Do not be rude in speech (3:159)
Restrain Anger (3:134)
Be good to others (4:36)
Be dutiful to parents(17:23)
expected output:
Restrain Anger (3:134)
Do not be rude in speech (3:159)
Be good to others (4:36)
Be dutiful to parents(17:23)
sorted in terms of both the numbers and the serial no stays the same

Answer 1

In order to compare two pair of numbers, you can make comparisons like:
if(suratno[i] < suratno[i-1] || (suratno[i] == suratno[i-1] && ayatno[i] < ayatno[i-1])){
/* swap */
}
Or you can use one expression: expr = suratno * 10000 + ayatno. And make just one comparison:
if(expr[i] < expr[i-1]){
/* swap */
}
Also, I have a few observations about your algorithm/code:
Don't use using namespace std. Specially in big programs, because it can cause obscure bugs (see an example here). Instead use using std::<name> when you want to avoid std::. Ex. using std::string. In general, avoid using namespace xxxx.
I see you did parse the input lines manually, I prefer to use regular expressions, that are much more versatile and powerful, but requires a little learning.
When it's necessary to write an error message, always write to stderr stream cerr in C++.
In the sort algorithm, it's better start in 1 than 0, because the first item doesn't have a previous item to compare with.
Finally the swap can be done with an existent C++ function.
Here is your code reorganized and using regular expressions that I tried to explain as much as possible:
#include <iostream>
#include <fstream>
#include <string>
#include <regex>
#include <vector>
#include <algorithm>
using std::string;
struct Line {
int expr; // Expression used to compare
string text; // Original line without initial number
};
int main() {
std::regex linePattern(
"\\d+" // 1 or more digits
"\\. " // '. ' (dot followed by 1 space)
"(" // begin char group #1
".*" // zero or more chars
"\\(" // '(' (left parenthesis)
"(\\d+)" // char group #2 (suratno: 1+ digits)
":" // ':' (colon)
"(\\d+)" // char group #3 (ayatno: 1+ digits)
"\\)" // ')' (right parenthesis)
")" // end char group #1
);
std::smatch groups; // Regular expression found char groups
std::vector<Line> lines; // Vector to store the readed lines
// Read lines parsing content
std::ifstream fin("text.txt");
if(!fin){
std::cerr << "Cannot open file 'text.txt'! Quitting.\n";
return 1;
}
string line;
while (std::getline(fin, line))
if (std::regex_search(line, groups, linePattern) && groups.size() > 0) {
int suratno = std::stoi(groups[2]);
int ayatno = std::stoi(groups[3]);
int compExpr = suratno * 10000 + ayatno; // assumes ayatno < 10,000
lines.push_back({ compExpr, groups[1] });
}
fin.close();
// sort algorithm (better start in 1)
for (size_t i = 1; i < lines.size(); i++)
for (size_t j = i; j > 0 && lines[j].expr < lines[j - 1].expr; j--)
std::swap(lines[j], lines[j - 1]);
std::ofstream fout("newtext.txt");
if(!fout){
std::cerr << "Cannot open output file 'orderedquranorders.txt'! Quitting.\n";
return 1;
}
for (size_t i = 0; i < lines.size(); i++)
fout << i + 1 << ". " << lines[i].text << std::endl;
fout.close();
std::cout << lines.size() << " orders successfully sorted and written.\n";
return 0;
}
Note: The regular expression is really one string "\\d+\\. (.*\\((\\d+):(\\d+)\\))", I used a C/C++ feature that concatenates strings separated by spaces before compilation, so the compiler sees only one string.
Don't forget to compile with -std=c++11 option.

Answer 2

using namespace std; is considered bad practice and can be dangerous sometimes. Check this
Here is your solution:
#include <iostream>
#include <fstream>
#include <string>
int main()
{
int suratno[100], ayatno[100];
std::string order[100];
char ch;
int count = 0;
int tempInt;
std::string tempStr;
std::ifstream fin;
fin.open("text.txt");
if (!fin)
{
std::cout << "Cannot open file \'text.txt\'! Quitting.\n";
exit(0);
}
else
{
while (fin)
{
fin.get(ch); //gets the numbers
fin.get(ch); //gets .
getline(fin, order[count], '('); //allegedly it removes the delimiter char from stream too
fin >> suratno[count];
fin.get(ch); //gets :
fin >> ayatno[count];
fin.get(ch); //gets )
fin.get(ch); //gets \n
std::cout << count + 1 << "." << order[count] << "(" << suratno[count] << ":" << ayatno[count] << ")\n";
count++;
}
}
fin.close();
std::cout << std::endl;
// sort algorithm (we must sort two times)
for (int i = 0; i < count; i++)
{
for (int j = i; j > 0 && suratno[j] < suratno[j - 1]; j--)
{
tempInt = suratno[j];
suratno[j] = suratno[j - 1];
suratno[j - 1] = tempInt;
tempInt = ayatno[j];
ayatno[j] = ayatno[j - 1];
ayatno[j - 1] = tempInt;
tempStr = order[j];
order[j] = order[j - 1];
order[j - 1] = tempStr;
}
}
for (int i = 0; i < count; i++)
{
for (int j = i; j > 0 && suratno[j] == suratno[j - 1] && ayatno[j] < ayatno[j - 1]; j--)
{
tempInt = ayatno[j];
ayatno[j] = ayatno[j - 1];
ayatno[j - 1] = tempInt;
tempInt = suratno[j];
suratno[j] = suratno[j - 1];
suratno[j - 1] = tempInt;
tempStr = order[j];
order[j] = order[j - 1];
order[j - 1] = tempStr;
}
}
// print the sorted list just to check
for (int i = 0; i < count; i++)
{
std::cout << i + 1 << "." << order[i] << "(" << suratno[i] << ":" << ayatno[i] << ")\n";
}
// write sorted list to output file
std::ofstream fout;
fout.open("newtext.txt");
if (!fout)
{
std::cout << "Cannot open output file\'orderedquranorders.txt\'!Quitting.\n";
exit(0);
}
else
{
for (int i = 0; i < count; i++)
{
fout << i + 1 << "." << order[i] << "(" << suratno[i] << ":" << ayatno[i] << ")\n";
}
}
fout.close();
std::cout << std::endl;
std::cout << count << " orders successfully sorted and written.\n";
return 0;
}