Essentially, the objective is to read an input file (hence inFile and inFileName) and output a population growth with asterisks representing each 1000 people using an ID (ex. 1375892), going from the year 1900 to 2020 in 20-year increments.
So, 1 asterisk for 1000 people, 3 asterisks for 3000 people, etc. The input file has numbers like 5000 and 7000 that I need to use to calculate the number of asterisks I need (by dividing by 1000). Even with that, I'm trying to figure out the final step in converting asteriskNum (the number of asterisks I need to use) and have it output the string of asterisks, not an integer of how many asterisks I need.
I definitely know I'm missing SOMETHING, but even after asking my teacher and scouring through my textbook and notes, I can't figure out how to solve this specific issue.
#include<iostream>
#include<iomanip>
#include<string>
#include<fstream>
using namespace std;
int main(){
string asterisk = "*";
string firstName;
int PopNum{0};
int year{1900};
int asteriskNum{};
const string INTROLINE{"POPULATION GROWTH \n(each * represents 1000 people)"};
cout << INTROLINE << "\n";
string inFileName="DL8_L5_Morrison.txt";
ifstream inFile{inFileName};
if (inFile){
cout << inFileName << " opened for reading. \n";
inFile >> firstName;
while (not inFile.eof()){
inFile >> PopNum;
asteriskNum = PopNum/1000;
cout << year << " " << asteriskNum << " " << << "\n";
year+=20;
inFile.close();
}
else {
cout << inFileName << " did not open for reading. \n";}
cout<<"Goodbye!\n";
return EXIT_SUCCESS;
}
}
You can use a std::string object and use the constructor that takes a count and character as arguments (constructor version #2 here). This will work with an int for the count argument, but it is better to cast it to a size_t type (or just have the calculated value as a size_t in the first place):
//...
asteriskNum = PopNum/1000;
cout << year << " " << std::string(static_cast<size_t>(asteriskNum), '*') << std::endl;
//...
First off, is it possible?
To extrapolate the question: I'd like to read some integers from a file, which is relatively simple for me.
However, when I read these values, which are formatted: "123 17 24 55 04 30 09" for example, my written output shows "123 17 24 55 4 30 9", where the "0" is absent before the 4, and the 9. This bothers me from a formatting aspect. How do I retain the 0 which is infront of the 4, and 9, in my output?
My current code is attached
int main() {
ifstream inf;
ofstream of;
float timeSmin, timeSsec, timeBmin, timeBsec=01.00, timeRmin=01, timeRsec=01.00;
int ID, totaltime;
inf.open ("triath.txt");
of.open ("output.txt");
if (!inf.is_open()){
cout << "Triath.txt cannot be opened, error..." << endl;
}
inf >> ID >> timeSmin >> timeSsec >> timeBmin >> timeBsec >> timeRmin >> timeRsec; //writing values to input object.
of << ID << " " << timeSmin << " " << timeSsec << " " << timeBmin << " " << timeBsec << " " << timeRmin << " " << timeRsec;
inf.close();
of.close();
return 0;
} ```
I would read the file in as a string and parse the string. That gives you the original string to use for output.
You'll need a way of splitting your input string into tokens. If you can't figure that out, you can do a google for "c++ split string by spaces" and get a bunch of good hits.
You'll need to then convert substrings into integers. Again, a google for "c++ convert string to integer" will provide some clues.
Then you just output the original string as is, and it's identical to what you originally read.
I read points frome a file, I use the library Lemon (because i want to use graph later) therefore each point is represented by the type : dim2 :: Point .
so I used the library lemon/dim2.h
My problem is that each point there have a number of the frame of the video, so i used this code to put variables from file in a vectors:
std::ifstream file("file1.txt");
std::vector<dim2::Point<int>> pointTable;
std::vector<int> frame;
int temp, temp2,temp3;
while (file >> temp >> temp2 >> temp3)
{
pointTable.push_back(dim2::Point<int>(temp, temp2));
frame.push_back(temp3);
}
//int tailleFmax = frame.max_size;
for (int i = 0; i < (36) ;i++)
//cout << frame[i] <<endl;
// cout << trajectoire[i].x << endl;
cout << trajectoire[i].y << endl;
My question : i dont know how to represent in c++ the connection betwen each point and his frame number and name this variable Trajectory.
Example of file :
155 // that is x
168 // that is y
0 // that is the frame number
364
245
20
546
156
I suspect that a map<int, dim2::Point<int>> is what you're looking for.
You could also simplify your code by reading in the point directly using dim2::Point's extraction operator: http://lemon.cs.elte.hu/pub/doc/latest-svn/a00862.html#g2dd3eccf5dece76c03bc6d1c2f348643
Your final code should look something like this:
ifstream file("file1.txt");
map<int, dim2::Point<int>> frame2PointTable;
pair<int, dim2::Point<int>> temp;
while(file >> temp.second >> temp.first) frame2PointTable.insert(temp);
To output this you could do something like:
for(const auto& i : frame2PointTable) cout << i.first << ": (" << i.second.x << ", " << i.second.y << ")\n";
Important notes:
Your example file contains 3 points but only 2 frame numbers, in this case only the 2 frame number-point combinations would be inserted
If you ever have multiple identical frame numbers in a file, only the first instance will be accepted by frame2PointTable
I've written you a live example using pair<int, int> instead of dim2::Point here: http://ideone.com/qtCZ8L
In this code, I want to have numbers printed in special format starting from 0 to 1000 preceding a fixed text, like this:
Test 001
Test 002
Test 003
...
Test 999
But, I don't like to display it as
Test 1
Test 2
...
Test 10
...
Test 999
What is wrong with the following C++ program making it fail to do the aforementioned job?
#include<iostream>
#include<string>
#include<fstream>
#include<iomanip>
using namespace std;
const string TEXT = "Test: ";
int main()
{
const int MAX = 1000;
ofstream oFile;
oFile.open("output.txt");
for (int i = 0; i < MAX; i++) {
oFile << std::setfill('0')<< std::setw(3) ;
oFile << TEXT << i << endl;
}
return 0;
}
The setfill and setw manipulators is for the next output operation only. So in your case you set it for the output of TEXT.
Instead do e.g.
oFile << TEXT << std::setfill('0') << std::setw(3) << i << endl;
As part of a school project, I would like to get an inventory *.txt file into an array in C++ and eventually back to a *.txt file at a later part in the program.
The text file will start out with 10 rows that will represent grocery story items and will include three columns that represent the name, price, and quantity of the items. I have been able to read from the file, even add numbers in front of each row that is displayed. Now, I would like to get the text file into a string array so that the "employee" user can make changes to items one at a time and then I can dump that array back into a *.txt file.
The code below is what I have been trying so far. I can get the count of rows in the file, but can't seem to get the columns counted or the data in the rows displayed. When I run the program, I get what appear to be 10 empty lines after it displays the rows (10) and Cols(0).
The columns in the *.txt file are normally separated by a space. I tried a tab, and tried: while(getline(invFile, lines, '\t'); which just caused the console to display what I am guessing was a memory address and then crashed.
Unfortunately, we have not gotten very far into debugging programs, and from the look of the syllabus, I don't think that will be covered very thoroughly, so I don't know how to troubleshoot any further. I have spent the last couple of hours Google-ing, and have gotten to the point that I actually need to ask for help.
The project involves a lot more than this component, but I really am stuck on this part. I am not asking for someone to do this for me, but if anyone has any idea what I am doing wrong and can point me in the best direction to get a text file into a multi-dimensional array, I would really appreciate it.
Thank you.
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <sstream>
#include <array>
int row = 0;
int col = 0;
using namespace std;
int main()
{
string lines;
int x;
string textArray[2][2];
ifstream invFile;
invFile.open("inventory.txt");
if(invFile.fail()){
cerr << "The file cannot be opened!";
exit(1);
}
cout << "\n" << endl;
while(invFile.good()) {
while(getline(invFile, lines)) {
istringstream streamA(lines);
col = 0;
while(streamA >> x) {
cout << x;
textArray[row][col] = x;
col++;
}
row++;
}
}
invFile.close();
cout << "Rows: " << row << endl;
cout << "Cols: " << col << endl;
cout << "\n" << endl;
for(int i=0; i<row; i++){
for(int j=0; j<col; j++){
cout << "Line: " << i << textArray[i][j] << ".";
}
cout << "\n";
}
return(0);
}
=============================
inventory.txt:
Apples 1.25 20
Oranges 1.75 20
Kiwi 2.50 15
Pineapples 5.50 20
Tomatoes 1.50 20
Onions 2.00 20
Corn 1.80 20
Carrots 2.30 20
Milk 4.50 20
Cheese 2.25 20
I would suggest that you create a struct or class to hold the data. From each line of text, extract the fields appropriately and them to your struct. Then, keep a list of those structs using std::vector.
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <sstream>
#include <array>
#include <vector>
#include <cstdlib>
using namespace std;
struct Row
{
vector<string> columns;
};
int main()
{
string line;
vector<Row> rows;
ifstream invFile;
invFile.open("inventory.txt");
if(invFile.fail()){
cerr << "The file cannot be opened!";
exit(1);
}
cout << "\n" << endl;
while(invFile.good()) {
while(getline(invFile, line))
{
Row row;
istringstream streamA(line);
string col;
while ( streamA >> col )
{
row.columns.push_back(col);
}
rows.push_back(row);
}
}
invFile.close();
cout << "Rows: " << rows.size() << endl;
cout << "Cols: " << rows[0].columns.size() << endl;
cout << "\n" << endl;
for(int i=0; i<rows.size(); i++){
for(int j=0; j<rows[i].columns.size(); j++){
cout << "Line: " << i << " " << rows[i].columns[j] << "\n";
}
cout << "\n";
}
return(0);
}
I'd like to suggest you add some print lines in the important step -- which I think also is a fast&good "debug" method. So that you can find where you wrong easily.
For example in your code, seems textArray wasn't assigned, so add some print nearby:
while(getline(invFile, lines)) {
cout <<"lines: " << lines << endl; //test enter here
istringstream streamA(lines);
col = 0;
while(streamA >> x) {
cout << "x is" << x; //test if enter here
textArray[row][col] = x;
col++;
}
row++;
}
Through the output, the lines is ok but cout << "x is" << x; wasn't printed, which means the while(streamA >>x) condition is false, why?
Go to find the library function called, std::istringstream x is int type but col 1 value is Apples, operator << will return NULL, it's unreasonable assing Apples to an int, till now, found point 1. If have to use int or float to store the numbers, use some convert API like atoi, atof.
After change x from int to string, got segmentation falut, it's obviously that textArray[2][2] is not enough to store all the information. "Out of range" is the reason of segmentation fault, so make a large array to test continue until passed.
There's a couple ways you could do this. The easiest would be to just put something like 3,10 at the top of the file, and then you know three columns and 10 rows. Since your writing this after modification, you would just need to make sure that those numbers get written correctly.
If you want to learn some more advanced methods, then your life will be easier AFTER you learn a bunch more.
If you used a vector, using something like vector< vector<string> > you could just read to a stringstream and then split the line read and put it into the vector
fstream file(...);
string tempString;
vector< vector<string> > list;
// Get a full line
while(getline(file, tempString, '\n'){
// Create a StringStream and store tempString in it for further manipulation
stringstream ss;
ss << tempString;
vector<string> tempVec;
// Get each column from this row
while(getline(ss, tempString, '\t'){
// Put each column into a vector
tempVec.push_back(tempString);
}
// Put the entire vector into our list vector
list.push_back(tempVec);
}
The benefit of this second method is twofold. First, it's very easy. I'm guessing you don't know how it works, but some easy Google searches on keywords you don't know, and you'll find out fast enough. The second is it allows (theoretically) unlimited rows, and unconstrained columns. By that, I mean one row could have 20 columns, one could have 2, and there would be no wasted space.
Note that you should NOT use the skeleton code I showed before researching it. If you don't have at least a general idea of what is happening here, then you'll just cause problems for yourself later on. I'm not going to explain everything here, because other people have done that already. Also, since you're learning this in school, you'll get to these things eventually, so you'll just be getting ahead. The one main constraint would be if your project requires arrays, in which case, my first solution would be the best option.