I need a lesson on HOW TO read input data, write input data, and write to the output file. Can anyone explain this to me? I ended up missing class yesterday because I was sick. I just need to know how to do it so I can do my homework. Any help would be greatly appreciated.
check the tutorials. They are there exactly for that. http://www.cprogramming.com/
Originally Posted by brewbuck:
Reimplementing a large system in another language to get a 25% performance boost is nonsense. It would be cheaper to just get a computer which is 25% faster.
I read the tutorial and I figured out how to at least create the input file and the output file. My problem, however, is how to pull just certain information from the file. For example, I have 3 categories that are characters, then I have a float which represents money, then I have integers which represents a number of people. When I set it up in my file, it is set up like this:Originally Posted by Mario F.
character, float, int
character, float, int
character, float, int
How do I pull just the integers from each line?
1. You read line into string buffer (using getline for example)
2. You parse the buffer, till you find what you need, ignoring the rest (using stringstream for example)
All problems in computer science can be solved by another level of indirection,
except for the problem of too many layers of indirection.
– David J. Wheeler
This is my problem, I don't understand how to do that. I'm just a beginner. In fact, this was only my 4th class, which I missed because of being ill. My book is almost worthless to me as everything it uses as examples uses strings. I need to take these integers and average them so I don't think strings are an option.
Last edited by dispatch4599; 02-05-2008 at 11:09 PM.
You could start by writing at least SOME code like
And write what you are doing with comments step by-stepCode:#include <string> int main() { std::string input; // here I will read string from file into input // for now I will test it with hard-coded string input = "A, 10, 1.1"; //And here I will try to extract int from string }
If on some step - you fail to aachive your goal (compilation error you do not know how to solve, or output you do not expect, or you do not know how to perform a specific task) - post your code and ask specific question
All problems in computer science can be solved by another level of indirection,
except for the problem of too many layers of indirection.
– David J. Wheeler
vart is right:
you should begin somewhere, then try to get closer to the solution, step by step.
http://www.cplusplus.com/reference/c...dlib/atoi.html
atoi ()
this c-standard function may help you, since it transforms a string into an integer.
Better use strtol instead of atoi.
When parsing the buffer, strtof might help in getting rid of float values.
Met with the professor today for a few minutes and got this far with the assignment. I am still having the problem, however, the results are not what they are supposed to be. What am I doing wrong???? I'm not looking for a solution to the problem just how do I get to the correct solution. Thank you much.Code:#include <iostream> #include <fstream> #include <cmath> #include <iomanip> using namespace std; void main() { //Declare and open files ifstream PayinFile; ofstream PayoutFile; PayinFile.open ("C: PayinFile.txt"); PayoutFile.open ("C: PayOut.txt"); //Declare variables char Cat1,Cat2,Cat3; float Pay1,Pay2,Pay3; int EmpNr1,EmpNr2,EmpNr3; float avgNum; //Read in data from file inData PayinFile>> Cat1 >> Pay1 >>EmpNr1 >> Cat2 >> Pay2 >> EmpNr2 >> Cat3 >> Pay3 >> EmpNr3; //Calculations avgNum = (EmpNr1 + EmpNr2 + EmpNr3)/3; PayoutFile << fixed << setprecision(2) << "The average number of Employees is " << avgNum << " ." << endl; PayinFile.close(); PayoutFile.close(); }
PayinFile.open ("C:\\PayinFile.txt");
Same for the other file.
No, not void main. Did your professor teach you to use that?
You should use int main. Void main is undefined. Bad.
I'm thinking you get bad results due to the layout of your file.
My Hat of Guessing thinks that you're actually expecting (EmpNr1 + EmpNr2 + EmpNr3)/3 to give you a floating-point value. If you actually want an accurate answer, you'll need to involve a floating-point number in the problem somewhere; the easiest way to do this is to change "3" to "3.0".
Yes he taught us to use void main.
Gah! Tell your professor to use "int main" because "void main" is undefined and very bad.
If he doesn't believe you, tell him to check cboard.cprogramming.com or http://cpwiki.sf.net/Void_main or http://faq.cprogramming.com/cgi-bin/...&id=1043284376 or http://cboard.cprogramming.com/showthread.php?t=96659.
Just tell him not to teach students to use void main!
Code:#include <iostream> #include <fstream> #include <cmath> #include <iomanip> using namespace std; int main() { //Declare and open files ifstream PayinFile; ofstream PayoutFile; PayinFile.open ("C:\\PayinFile.txt"); PayoutFile.open ("C:\\PayOut.txt"); //Declare variables char Cat1,Cat2,Cat3; float Pay1,Pay2,Pay3; int EmpNr1,EmpNr2,EmpNr3; float avgNum; //Read in data from file inData PayinFile>> Cat1 >> Pay1 >>EmpNr1 >> Cat2 >> Pay2 >> EmpNr2 >> Cat3 >> Pay3 >> EmpNr3; //Calculations avgNum = (EmpNr1 + EmpNr2 + EmpNr3)/3.0; PayoutFile << fixed << setprecision(2) << "The average number of Employees is " << avgNum << " ." << endl; PayinFile.close(); PayoutFile.close(); return 0; }
This is impossible.
The average number of Employees is 572662336.00 .
This is my PayinFile.
X 19312.34 34
Y 26825.12 56
Z 28562.50 80
Indeed. In fact, if you run the code you gave on the input file you gave, you get an output of 56.00. So either you did not, in fact, run that code, or (more likely) you did not use that input file. Are you sure your path is correct? You don't check that any of your file opens actually works -- print out what EmpNr1 (etc.) are because you might just be reading from nowhere.
And edit to note: 56.00 isn't the right answer either; see my other post.
