I am trying to open a text file and pass the lines of the text file to a vector. The first digit in each line is the size of the vector and since I do not know the end point of the text file I am using a while loop to find the end. The idea is that I can take a text file and run a merge sort on it. So, for example:
3 5 4 9
5 0 2 6 8 1
sorted it would be become:
4 5 9
0 1 2 6 8
The problem I am having is that when I sort a vector that is larger than the prior vector (as in the example) I do not get output. It is probably something simple that I just have over looked. I am pretty sure the issue is in the code below. Thanks for any pointers.
while (!file.eof())
{
int size;
file >> size;
vector<int> myVector(size);
int n = 0;
while (n < size && file >> myVector[n])
{
++n;
}
sort(myVector);
for (int j = 0; j < size; ++j)
{
if (file.eof()) break;
cout << myVector[j] << ' ';
}
cout << '\n';
}
The problem is this line:
if (file.eof()) break;
Once you've read the last line of the file, file.eof() will be true. So the first time through the loop that's supposed to print the sorted vector, you break out of the loop and don't print anything. It has nothing do with whether the vector is larger than the previous vector, it's just a problem with the last line of the file. The fix is to get rid of that unnecessary line.
You also need to change the main loop. while (!file.eof()) is the wrong way to loop over a file's contents (see the linked questions for full explanations). Use:
int size;
while (file >> size) {
...
}
because of the line :
if(file.eof()) break;
if you get to eof your program wont print anything since you break the printing loop on its first iteration
for instance - if there are no chars after 8 in your example - you wont get output ,but even a single space can change that
besides that - is there any chance or cases that your sorting function clears a vector ? or changes it ?
Related
hello i am a beginner in programming and am in the array lessons ,i just know very basics like if conditions and loops and data types , and when i try to solve this problem.
Problem Description
When Serezha was three years old, he was given a set of cards with letters for his birthday. They were arranged into words in the way which formed the boy's mother favorite number in binary notation. Serezha started playing with them immediately and shuffled them because he wasn't yet able to read. His father decided to rearrange them. Help him restore the original number, on condition that it was the maximum possible one.
Input Specification
The first line contains a single integer n (1⩽n⩽105) — the length of the string. The second line contains a string consisting of English lowercase letters: 'z', 'e', 'r', 'o' and 'n'.
It is guaranteed that it is possible to rearrange the letters in such a way that they form a sequence of words, each being either "zero" which corresponds to the digit 00 or "one" which corresponds to the digit 11.
Output Specification
Print the maximum possible number in binary notation. Print binary digits separated by a space. The leading zeroes are allowed.
Sample input:
4
ezor
Output:
0
Sample Input:
10
nznooeeoer
Output:
1 1 0
i got Time limit exceeded on test 10 code forces and that is my code
#include <iostream>
using namespace std;
int main()
{
int n;
char arr[10000];
cin >> n;
for (int i = 0; i < n; i++) {
cin >> arr[i];
}
for (int i = 0; i < n; i++) {
if (arr[i] == 'n') {
cout << "1"
<< " ";
}
}
for (int i = 0; i < n; i++) {
if (arr[i] == 'z') {
cout << "0"
<< " ";
}
}
}
Your problem is a buffer overrun. You put an awful 10K array on the stack, but the problem description says you can have up to 100K characters.
After your array fills up, you start overwriting the stack, including the variable n. This makes you try to read too many characters. When your program gets to the end of the input, it waits forever for more.
Instead of putting an even more awful 100K array on the stack, just count the number of z's and n's as you're reading the input, and don't bother storing the string at all.
According to the compromise (applicable to homework and challenge questions) described here
How do I ask and answer homework questions?
I will hint, without giving a code solution.
In order to fix TLEs you need to be more efficient.
In this case I'd start by getting rid of one of the three loops and of all of the array accesses.
You only need to count two things during input and one output loop.
I am reading string from a line in a text file and for some reason the the code will not read the whole text file. It reads to some random point and then stops and leaves out several words from a line or a few lines. Here is my code.
string total;
while(file >> word){
if(total.size() <= 40){
total += ' ' + word;
}
else{
my_vector.push_back(total);
total.clear();
}
Here is an example of a file
The programme certifies that all nutritional supplements and/or ingredients that bear the Informed-Sport logo have been tested for banned substances by the world class sports anti-doping lab, LGC. Athletes choosing to use supplements can use the search function above to find products that have been through this rigorous certification process.
It reads until "through" and leaves out the last four words.
I expected the output to be the whole file. not just part of it.
This is how I printed the vector.
for(int x = 0; x< my_vector.size(); ++x){
cout << my_vector[x];
}
You missed two things here:
First: in case when total.size() is not <= 40 i.e >40 it moves to else part where you just update your my_vector but ignore the current data in word which you read from the file. You actually need to to update the total after total.clear().
Second: when your loop is terminated you ignore the data in word as well. you need to consider that and push_back()in vector (if req, depends on your program logic).
So overall you code is gonna look like this.
string total;
while(file >> word)
{
if(total.size() <= 40)
{
total += ' ' + word;
}
else
{
my_vector.push_back(total);
total.clear();
total += ' ' + word;
}
}
my_vector.push_back(total);//this step depends on your logic
//that what u actually want to do
Your loop finishes when the end of file is read. However at this point you still have data in total. Add something like this after the loop:
if(!total.empty()) {
my_vector.push_back(total);
}
to add the last bit to the vector.
There are two problems:
When 40 < total.size() only total is pushed to my_vector but the current word is not. You should probably unconditionally append the word to total and then my_vector.push_back(total) if 40 < total.size().
When the loop terminated you still need to push_back() the content of total as it may not have reached a size of more than 40. That is, if total is no-empty after the loop terminated, you still need to append it to my_vector.
I have a .txt file which I'm trying to gather data from, that can then be used within variables within my code to be used in other functions.
Here's an example of my text file:
0 10 a namez 1 0
0 11 b namea 1 1
1 12 c nameb 1 1
2 13 d namec 0 1
3 14 e named 1 1
So my file will not always be the same number of lines, but always the same number of variables per line.
I currently have this, to firstly get the length of the file and then change the amount of rows within the array:
int FileLength()
{
int linecount = 0;
string line;
ifstream WorkingFile("file.txt");
while(getline(WorkingFile, line))
{
++linecount;
}
return linecount;
}
int main()
{
string FileTable [FileLength()][6];
}
Firstly I don't know if the above code is correct or how I can add the values from my file into my FileTable array.
Once I have my FileTable array with all the file data in it, I then want to be able to use this in other functions.
I've been able to do:
if(FileTable[2][0] = 1)
{
cout << "The third name is: " << FileTable[2][3] << endl;
}
I understand my code may not make sense here but I hope it demonstrates what I'm attempting to do.
I have to do this for a larger text file and all the 6 variables per line relate to be input to a function.
Hold each line in its own object, this is much clearer:
struct Entry
{
std::array<std::string, 6> items; // or a vector
};
In main:
std::vector<Entry> file_table( FileLength() );
Note that it is a waste of time to read the whole file first in order to find the number of entries. You could just start with an empty vector, and push in each entry as you read it.
Your access code:
if( file_table.size() > 2 && file_table[2].items[0] == "1" )
{
cout << "The third name is: " << FileTable[2].items[2] << endl;
}
I would actually recommend giving the members of Entry names, instead of just having an array of 6 of them. That would make your code more readable. (Unless you really need to iterate over them, in which case you can use an enum for the indices).
You could define an operator[] overload for Entry if you don't like the .items bit.
since the number of lines is dynamic I suggest to use vector instead of array. you can push back your data to the vector line by line until you read eof.
also try to study about OOP a little , it would make your code more understandable.
take look at these:
http://www.cplusplus.com/reference/vector/vector/
http://www.geeksforgeeks.org/eof-and-feof-in-c/
int lineInputs = 0;
cin >> lineInputs;
int whatever = 0;
char* myArray = new char[arrayElements*lineInputs];
int j =0;
for(int i = 0; i < lineInputs; i++)
{
cin >> whatever;
for(j; j<total; j+=39)
{
for(int nom=0; j<arrayElements; nom++)
{
cin >> myArray[j];
}
}
}
In my forloop say i have lineInputs = 4 and total = 156
Meaning 4 times we do this, we want to insert 156 chars into my array. But we want to make it so that every 40 characters we continue entering the array.
Bsically we need to insert this input into the array but i feel like my forloops are messed up. This will be the input
4
1
HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
2
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
3
HHTTTHHTTTHTHHTHHTTHTTTHHHTHTTHTTHTTTHTH
4
HTHTHHHTHHHTHTHHHHTTTHTTTTTHHTTTTHTHHHHT
The first line 4 meaning 4 of these 40 character lines. And the number above the character lines just signifying line 1 2 3 4 ect.
How can i attempt this right?
So the array would basically look like this.
HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTHHTTTHHTTTHTHHTHHTTHTTTHHHTHTTHTTHTTTHTHHTHTHHHTHHHTHTHHHHTTTHTTTTTHHTTTTHTHHHHT
You are making the same fundamental mistake you made in your other question, which is to fail to treat the input array correctly. You are repeatedly reading into the first 40 characters of myArray. What you need to do is read the first line into the first 40 characters, the second line into characters 40 to 79, etc.
Better yet, make it a two dimensional array so that you don't have to muck around with computing the indices.
Even better, make it an array of std::string rather than an array of char.
I'm learning c++ and got the project to send a pascal's triangle to output (after n-rows of calculation)., getting output like this, stored in a stringstream "buffer"
1
1 1
1 2 1
1 3 3 1
But what I want is rather
1
1 1
1 2 1
1 3 3 1
My idea was: calculate the difference of the last line and current line length (I know that the last one is the longest). Then pad each row using spaces (half of the line-length-difference).
My Problem now is:
I didn't get how getLine works, neither how I might extract a specific (-> last) line
I don't know and could not find how to edit one specific line in a stringstream
Somehow I got the feeling that I'm not on the best way using stringstream.
So this is rather a common question: How'd you solve this problem and if possible with stringstreams - how?
To know the indentation of the first line, you would need to know the number of lines in the input. Therefore you must first read in all of the input. I chose to use a vector to store the values for the convenience of the .size() member function which will give the total number of lines after reading in all input.
#include<iostream>
#include<sstream>
#include<vector>
#include<iomanip> // For setw
using namespace std;
int main()
{
stringstream ss;
vector<string> lines;
string s;
//Read all of the lines into a vector
while(getline(cin,s))
lines.push_back(s);
// setw() - sets the width of the line being output
// right - specifies that the output should be right justified
for(int i=0,sz=lines.size();i<sz;++i)
ss << setw((sz - i) + lines[i].length()) << right << lines[i] << endl;
cout << ss.str();
return 0;
}
In this example, I am using setw to set the width of the line to be right justified. The padding on the left side of the string is given by (sz - i) where sz is the total number of lines and i is the current line. Therefore every subsequent line has 1 less space on the left hand side.
Next I need to add in the original size of the line (lines[i].length()), otherwise the line will not contain a large enough space for the resulting string to have the correct padding on the left hand side.
setw((sz - i) + lines[i].length())
Hope this helps!
If you have access to the code that writes the initial output, and if you know the number of lines N you are writing, you could simply do:
for(int i = 0; i < N; ++i) {
for(int j = 0; j < N - 1 - i; ++j)
sstr << " "; // write N - 1 - i spaces, no spaces for i == N.
// now write your numbers the way you currently do
}