C++ :: Outputting Data From File Into Structs And Arrays Of Structs
Apr 15, 2013
I am having a lot of trouble being able to get data from a file and input it into given structs and arrays of structs and then outputting the file. We are given a file that contains 96 lines and looks like this:
Arzin, Neil
2.3 6.0 5.0 6.7 7.8 5.6 8.9 7.6
Babbage, Charles
2.3 5.6 6.5 7.6 8.7 7.8 5.4 4.5
This file continues for 24 different people and then repeats with different scores (the second line).
The first number, in this case is 2.3 for both people is a difficulty rating. The next 6 numbers are scores.
We are given this data in order to set up our structs and arrays and my code:
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <cmath>
using namespace std;
int main () {
ifstream inFile;
inFile.open("C://diveData.txt);
The main is not working properly, I get strange missing parenthesis notices and array errors which I am not understanding. How to identify the errors. Functions are included.
Code: #include <stdio.h> #include <stdlib.h> #include <string.h> int menu (); double change_value (double * value);
Write a program for the following problem. You're given a file that contains a collection if IDs and scores (type int) for an exam in your computer course. You're to compute the average of these scores and assign grades to each student according to the following rule:
If a student's score is within 10 points (above or below) of the average, assign a grade of satisfactory. If a studnt's score is more than 10 points above average, assign a grade of outstanding. If a student's score is more than 10 points below average, assign a grade of unsatisfactory.
The output from your program should consist of a labeled three-column list that shows each ID, score, and corresponding grade. Use a struct to store each student's data and an array of structs to store the whole class. The struct should have a data member for id, score, and grade.
I wrote this code for a homework assignment, everything runs fine but the function void percent_votes (line 66) isn't calculating properly, it outputs 0.00 for each value. I have tried everything I can think of to try and make it work.
Here is the assignment: Write a program that allows the user to enter the last names of five candidates in a local election and the number of votes received by each candidate. The program should then output each candidate's name, the number of votes received, and the percentage of the total votes received by the candidate. Your program should also output the winner of the election.
I am increasing my array in multiples of 5 (or in this case, my constant BLOCK). This is the result of my printout (t1-t40 is correct, the rest of the values should be 1):
t1 1 1 t2 1 1 t3 1 31329 t4 31297 1 t5 1 31249 t6 31217 1 and so on .....
I noticed that in my test, realloc was called 7 times. My array has 7 distorted records. Each time I call realloc, it is distorting one of my records.
The program takes as input a pair of triangles, specified be giving the coordinates of each trangle's vertices. It then determines if either triangle is "nested" within the other, meaning that one triangle lies entirely within the interior of the other.
Pseudocode:
One triangle lies within another if and only if all three vertices of the first triangle lie within the interior of the second triangle.
Suppose that we have a triangle with vertices A, B, and C, described by the coordinates (xA, yA), (xB, yB), and (xC, yC), respectively. The sides of the triangle are the line segments AB, BC, and CA.
A line passing through two points (x1, y1) and (x2, y2) can be considered to be the set of points (x,y) satisfying the equation
f(x,y) = 0 where f(x,y) is given as f(x,y) = (x - x1) (y2 - y1) - (y - y1) (x2 - x1)
One of the interesting things about that f(x,y) is that we can use it to determine which "side" of the line an abitrary point (x,y) is on:
If f(x,y) = 0, the point is exactly on the line. All points for which f(x,y) > 0 are on one side of the line, and All points for which f(x,y) < 0 are on the other side So the problem of determining whether a point (x,y) is on the inside of a trangle can be checking the sign of f(x,y) for each of the three lines making up the triangle. A complicating factor is that we don't know, for any given triangle, whether those three signs should be all positive, all negative, or some mixture of the two.
The centroid of a triangle can be computed as the "average" of the x and y coordinates of the vertices:
xcen = (xA + xB + xC)/3 ycen = (yA + yB + yC)/3
This point (xcen, ycen) is definitely inside the trangle (unless the triangle is "degenerate" and has no interior points). The problem of determining whether (x,y) is on the inside of a triangle can therefore be resolved by checking to see if it is on the same side of each of the trangle's line segments as (xcen, ycen).
What I need:
I want to fill in the missing bodies for the functions eval and areOnSameSideOf, which manipulate line segments. I think calling eval from within areOnSameSideOf will simplify the implementation of the latter.
The program takes as input a pair of triangles, specified be giving the coordinates of each trangle's vertices. It then determines if either triangle is "nested" within the other, meaning that one triangle lies entirely within the interior of the other.
Pseudocode:
One triangle lies within another if and only if all three vertices of the first triangle lie within the interior of the second triangle.Suppose that we have a triangle with vertices A, B, and C, described by the coordinates (xA, yA), (xB, yB), and (xC, yC), respectively. The sides of the triangle are the line segments AB, BC, and CA.A line passing through two points (x1, y1) and (x2, y2) can be considered to be the set of points (x,y) satisfying the equation
f(x,y) = 0 where f(x,y) is given as f(x,y) = (x - x1) (y2 - y1) - (y - y1) (x2 - x1)
One of the interesting things about that f(x,y) is that we can use it to determine which "side" of the line an abitrary point (x,y) is on:
If f(x,y) = 0, the point is exactly on the line.
All points for which f(x,y) > 0 are on one side of the line, and All points for which f(x,y) < 0 are on the other side So the problem of determining whether a point (x,y) is on the inside of a trangle can be checking the sign of f(x,y) for each of the three lines making up the triangle.
A complicating factor is that we don't know, for any given triangle, whether those three signs should be all positive, all negative, or some mixture of the two.
The centroid of a triangle can be computed as the "average" of the x and y coordinates of the vertices:
xcen = (xA + xB + xC)/3 ycen = (yA + yB + yC)/3
This point (xcen, ycen) is definitely inside the trangle (unless the triangle is "degenerate" and has no interior points).
The problem of determining whether (x,y) is on the inside of a triangle can therefore be resolved by checking to see if it is on the same side of each of the trangle's line segments as (xcen, ycen).
I want to fill in the missing bodies for the functions eval and areOnSameSideOf, which manipulate line segments. I think calling eval from within areOnSameSideOf will simplify the implementation of the latter.
Code: #include <iostream> using namespace std; /** * 2D Cartesian coordinates */ struct Point { double x; double y;
Where course code is the 4 numbers after the name together and the term is the letter and year in the last two pieces of info. I got this to work:
int main() { FILE *p; p = fopen("input.csv", "r+"); if(p == NULL) { puts("The file could not be opened");
[Code] ......
But lets say i dont know how many lines i have in my file and i want to count them and then use that size for my array so i tried this by:
int main() { FILE *p; int lines = 1; char ch; p = fopen("input.csv", "r+"); if(p == NULL) {
[Code] .....
But the second program is not working for unknown reasons. I do not get any errors but its not scanning the info because when i print the info later on it prints out random symbols.
And I want to make adding,deleting, and searching functions.Something like
Code:
void add();//Add name and address to a file, //and add more to the same file if I want to. void del();//Delete or Change some neighbor's name or address //in the same file(Can I?) void search();//Search name and show detail
So I started to code adding function first, but I don't know that I need to use pointer to code each functions relations, and I don't know how to check that my input's already exists yet. But I started some code below...
Code: void add() { int i=0; FILE *fp = fopen("neighborhood.txt", "at"); if ( fp != NULL ) { do{
I'm trying to read the data from a file i/o and put them into an array of structs. But when I run the program, it gives me a bunch of "garbage" as an output. my code and see
I'm working on a project involving nested classes and structs like this:
Code: class A { public:class B { public:f() {A::C* iCanDoThis; //no errors. iCanAlsoDoThis->root->.... //this also works fine.}private:A::C* iCannotDoThis //this is what I would like to do. Has errors A* iCanAlsoDoThis;};private:struct C {..data..};
C* root;};
Is it possible make a pointer to struct C a private member of class B?
I'm currently working on a program that writes an array of struct to a file and then read back the data from the file to another array of struct. At the bottom is an image of my result.
My goal is to end up with two identical struct arrays but my program fails to do this. My struct have to members: ID and kind (of animals in this case). I declare my first arraystruct africa[] with "monkey" and "giraffe" with their respectively IDnr: 112 and 555. I stream this data to a file and read read them back to the arraystruct get_animal[]. Simply I want the get_animal[] to be identical with the africa[] when the program is over, but that is not so. According to my result(bottom image) it display:
112, monkey (get_animal[0]) 112, monkey (get_animal[1]) meaning that get_animal[0] is identical to africa[0] get_animal[1] is also identical to africa[0]
but why? I want get_animal[1] to be identical with africa[1]. meaning I want the result to look like this:
112, monkey 555, giraffe
I've also made the program to print the parameters of my fwrite/fread calls. Why is the 3rd parameter = 1 meaning that only 1 element will be read/written when my program just read/write 2 elements?
How would I be able to have this display the rest of the households without having to have 13 separate cout lines(one for each household)? In other words, how can I set it up to increment the output?
#include <iostream> #include <iomanip> #include <string> using namespace std;
I think i am getting confused with passing structs and functions all in the same...When I run through the program (it compiles), the functions that add coins do not add, but rather just replace an old value with a new one.
#include <cstdlib> #include <iostream> using namespace std; struct coinbox {
I can't seem to remember everything I should about constructors. I'm looking for a way to create an array of structs, using a constructor. My code should explain.
struct myStruct { private: int structInt1, structInt2;
I get an error telling me that foo is undefined, and that declaration of function_example(int x, int y) is incompatible with the declaration of it in the header file.
I have an assignment where I need to use pointers to do a few things and I am a little confused on the syntax of it all. My question is how do you use a pointer to point to an array of structs.
For example
struct info{ char firstName[15]; char lastName[15]; }; main() { info person[4]; cout << "The third letter of the second persons first name is: "; // ????? }
how would I define a pointer to point to the third letter of first name the second person in the "person" array.
How to fill a vector with structs that are read in from a separate file. Each line in the file would read for example "Doe John M 26" for the name of the person, gender and age. I just need to get pointed in the right direction so I can get this started.
what I am trying to do is to pass to a function the address of an array of structs, so I can later modify the items within the struct, within the array
Code: typedef struct { //A struct of name auctionint bidder;float bid;} auction; void myFunction (auction * auctionItem[]){(*aucItem[x]).bid = y;(*aucItem[x]).bidder = z;} int main(){auction theItems[10]; myFunction(theItems);} Where x, y, and z can be any number.
When I try to run my code the IDE (I'm using Code::Blocks 12.11) does not give me any errors, but it does give me a warning:
warning: passing argument 3 of '<function name>' from incompatible pointer type [enabled by default]
and the note:
note: expected 'struct <struct name> **' but argument is of type 'struct <struct name> *'.Also, when I run the program, it will crash and return garbage.
I have a structure product_array *pa that contains a pointer *arr to an array of structs and count that adds 1 when a new product is added (set to NULL initially). I have to write a function which adds a new product entry to that array. One product entry has *title, *code, stock and price parameters. The array is dynamically allocated and I’m supposed to:
1. Reallocate space for array. 2. Update product_array. 3. Initialize it.
Also, code should be truncated to 7 characters.Products can be added multiple times, so the initial size is unknown.
Code:
void add_product(struct product_array *pa, const char *title, const char *code, int stock, double price) { for (int i = 0 ;; i++){ pa->arr = realloc(pa->arr, sizeof(struct product_array));
