I am doing an exercise which has to do with International country codes.The user must give a code and the programm will display the corresponding country.
Code:
#include <stdio.h>
#define COUNTRY_COUNT
((int) (sizeof(country_codes) / sizeof(country_codes[0])))
[code]....
I have a program that stores health information the user inputs, one person at a time. The program works perfectly with the exception of storing the data...I need to open a file and read what health data it has in it already, if any, but store the new changes, and appended data to the array of structures, to the data in memory. All of the information is only saved back in the file once the program terminates. I'm not sure how to go about doing this, so I am also not sure what to put in the function for "Save and Exit" that the user can choose in order to exit the program.
Code:
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
struct strdatabase
{
char first[20];
char last[20];
char gender[2];
[Code]...
I tried playing around with this bit of code, but I'm not sure if I'm even on the right track.
Code:
FILE *fp;
fp = fopen ("students.txt","rb"); fseek(fp, 0, SEEK_END);
long pos = ftell(fp);
fseek(fp, 0, SEEK_SET);
char *bytes = malloc(pos);
fread(bytes, pos, 1, fp);
fclose(fp);
What is the difference between at performance level, if any, between the following cases, during assignment?
case 1: #define Value_16 16
and
case 2: #define Value_16 (1<<4)e.
write codes that could solve a quadratic formula, and my codes are like this:
#include <bjarne/std_lib_facilities.h>
int main()
{
cout << "Enter the coefficients of a quadratic polynomial a*x**2 + b*x +c:
";
cout << " a? ";
double a;
cin >> a;
cout << " b? ";
[code]....
Which runs perfectly, but I have 2 questions:
1. How to simplify these code? On the assignment sheet the professor wrote about using void solve_linear(double b, double c); and void solve_ quadratic (double a, double b, double c);which I currently dont understand how these works. He asked us to write a well-encapsulated (as short as possible) program.
2. These are for extra points: the precision problem of floating numbers: professor asked us to find a way to get the precise answer of it, like this: Enter the coefficients of a quadratic polynomial a*x**2 + b*x +c:
a? 1
b? -20000
c? 1.5e-9
Trying to solve the quadratic equation 1*x*x + -20000*x + 1.5e-09 == 0
Using classical formula: Two roots, x = 20000 and x = 0
Using stable formula: Two roots, x = 20000 and x = 7.5e-14
My guess is that
A. Using code like if(x1*x2=a/c) to check if numbers were approximated.
B. Somehow determine the larger one in x1 and x2.
C. Somehow use that larger one to do something
I have an assignment to write a program using structures, getting input from a .txt file and output in text file as well. I have written a program that only reads and prints the data. I am trying to test if it works fine or not. I always comment an unnecessary code but still it wont compile. Now whats wrong with this program?
/* Bank Accounts Program */
#include <iostream>
#include <string>
#include <fstream>
#include <cstdlib>//needed to use system() function
using namespace std;
const int MAX_NUM = 50;
void menu();
[Code]...
Write a program that accepts three values (int) from the keyboard into three variables a, b and c. After loading the variables, your program will arrange the values into a, b, and c, so that a contains the larger, be the next and c the smallest.
You can use any other variables in addition to a, b c, as you see fit.
You will have to use some variation(s) of the if construct.
There are many ways to program this, but your challenge will be to achieve this without doing all possible comparisons. In fact, three comparisons woudl be enough, if you , for example, determine the largest number first, and keep track of its position in some way , so you can compare the other two.
I think I might use a code similar to the one below.
switch (expression) {
case constant1:
group of statements 1;
break;
case constant2:
[Code] ....
How to write a program that will prompt and read 5 numbers. Then the program should print numbers that are larger than 80.
View 1 Replies View RelatedHow do I store pointers to a struct in an array ? I am using sprintf to concatenate some values together and then output it to an array in its 1st argument. A portion of my code is shown below.
Code:
int count = 0;
struct addx {
int a;
[Code].....
So i have a program with the structure
Code:
char record[20];
typedef struct{
int id;
char title[20];
char subject[20];
char faculty [20];
int level;
char fname[25];
}report;
int recno,i;
report list[100];
I need to store the hundred records into a file. What are the functions and elements i should use/introduce.
How to initialize this array of structures in my code
struct CustomerAddress; {
string street;
string city;
string state;
int zip;
[Code] ....
I am going to be using a boolean variable to mark whether or not a specific field has had data entered into it. I figure the best way to do that is to initialize all the elements of the structures to 0. However, with strings and with the nested structure, I'm not sure how to do this.
I am writing a employee payroll program using structures. My program is running but its only showing some of the data.
HERES MY CODE
Code:
#include <iostream>
#include <cstdio>
#include <fstream>
#include <string>
#include <iomanip>
#include <cstring>
using namespace std;
const int SZ = 20; // size of arrays to hold scores
struct payrollStruct {
[Code] ....
And it doesn't show anything from txt file
Code:
40.0 10.00 A1234 Jane Adams
50.0 10.00 L8765 Mary Lincoln
25.5 10.85 W7654 Martha Washington
52.0 15.75 A9876 John Adams
45.0 25.00 W1235 George Washington
[Code] .....
I have to write a program that reads from a text file, which contains a list of stock hourly prices and the company names. Something like this:
78.52 82.56 75.10 71.97 Water Company
22.40 25.68 21.37 22.96 Mega Shipping Inc
There's suppose to one array of companies, where each company will be kept in a structure that contains: a pointer for the name, an array of the prices, and the average price for the day. The structures will be kept in an array of structures.
My question is, how do I read the data from the file and put the data from each line into the next structure in the array of structures? I read the numbers in fine. I just use:
Code: fscanf(fp, "%f", &companyAry[i].hourlyPrices[j]);
But my program crashes when I try to read the name.
Code: fscanf(fp, "%[^]", &companyAry[i].companyName);
I'm thinking it has something to do with the fact the companyName is a pointer.
My structure looks like this:
Code:
typedef struct {
char *companyName;
float hourlyPrices[NUM_PRICES];
float avgPrice;
}
COMPANY;
I have an array of structures with structure def that looks like.
Code:
struct {
char * name;
char * school;
int age;
}
there are multiple people with same name but different ages so i want to list them like.
Name.
age 1
age 2 and so on
The array is sorted by name already.
so im trying to read in the name of a vendor into an array of structures. and write the name into a file.
#include <iostream>
#include <cstring>
#include <cctype>
#include <fstream>
using namespace std;
struct booth
[code]....
Any example to delete an element in an array of structure?Is it same as deleting an element in an array.ie like this....???
// to delete an element in an array
#include<iostream.h>
#include<conio.h> // for clrscr() and getch()
void main() {
clrscr();
int a[50],n,t,index,i;
[Code] .....
I am making a basic music library that stores information rather than files. I need to read from a .txt file the artist's name, the album name, the song name, and the song length. What I am confused about is storing the information in an array of Artist structures.
struct Song{
string songName;
int songLength;
};
struct Album{
[Code] ...
How to read the information into an array of Artists. Also, how would I be able to figure out if the artist already exists in the array when adding a song and if the artist does, add the album under the existing artist.This is how I am reading in the info:
Artist newArtist;
Album newAlbum;
Song newSong;
ifstream inF("library.txt");
while(!inF.eof()) {
[Code] ....
Suppose I have the following structure
struct b
{
char fullname[100];
char title[100];
bopname
};
and i declare a pointer to the struct as follows
b* bp;
and at runtime,
bp = new b[5];
In the end, is the statement delete[ ] bp enough to release the dynamically allocated memory. Or do i need to separately delete bp[0],bp[1]...
Does delete[ ] bp indicate that the array[ ] pointed by bp has to be deleted?? [I am confused as to how this happens, since the pointer only points at the 1st struct address]
I somewhere read "You cannot initialize a structure like that at run time."
Example:
struct item_info {
char itemname[15];
int quantity;
float retail;
float wholesale;
[Code] ....
But if you want to assign values at run time then you have to do it manually like:
strcpy(item[0].itemname, "rice");
item[0].quantity = 10;
item[0].retail = 40;
item[0].wholesale = 30;
I tried in internet but am unable to know the differences. I want to know the difference between those two in terms of run time and compile time. Explanation required also for below one. Is this run time or compile time? How does we actually decide which is run time and which is compile time!
struct item_info {
char itemname[15];
int quantity;
float retail;
float wholesale;
//int quatityonorder;
[Code] ....
I'm reading the following file:
Osgood,Marcus 298542123 CHM FR mosgood@whatever.edu
Cronk,Melissa 873489021 BIO SR mcronk@whatever.edu
Pry,Seth 349908431 MTH SO spry@whatever.edu
Langlais,Susan 783323545 ME SR slanglais@whatever.edu
Davis,Nicole 987543345 PHY FR ndavis@whatever.edu
It's supposed to split it up into name, ID number, major, year, and email. The file reads it without any errors, and assigns name to the first part of the structure. However, ID gets assigned the ID, major, year, and email. Then Major gets assigned major, year, and email. Year gets assigned year and email, while email just gets assigned email. I don't know if it has something to do with the loop. For example, this is what I get what I print just the name and the ID.
Cronk,Melissa 873489021BIOSRmcronk@whatever.edu
Pry,Seth 349908431MTHSOspry@whatever.edu
Langlais,Susan 783323545ME
Davis,Nicole 987543345 PHYFRndavis@whatever.edu
Anyway. This is my function code for reading the array. I have it printing the ID number just to see if I can catch the errors earlier:
Code:
#include <stdio.h>
#include <string.h>
#include "functions.h"
void read_data(char filename[], studentinfo_t s[], int *size) {
FILE *infilep;
int countstudents = 0;
infilep = fopen("student_data", "r");
[Code].....
the name is reading correctly, but not anything else!
I have to allocate memory for an array of structures, and my structure looks as following:
Code:
typedef struct {
char *name;
Uint *start_pos;
Uint len;
}
example_struct;
And now I want to allocate memory, for a variable number (so an array) of example_struct, so I first do:
Code:
example struct *all_struct;
int total_num = 3;
//will be set somehow, but for the example I set it on 3 all_struct = malloc (sizeof(example_struct) * total_num);
And now, as far as I now, I will have to allocate for each field of the structure memory, in order to be able to use it later. But I have problem at this point, a problem of understanding:
- I just allocated memory for 3 structures, but don't I have to allocate then memory for each structure separately, or can I just now allocate the fields like this:
Code: all_struct[0].name = malloc.....
But if yes, why the hell this works...
Background: I'm writing a convolutional encoder (and decoder, eventually) for a microprocessor (PIC24), for which I'm using structs and pointers to move from state to state. So far as I'm aware, everything I'm using in the PIC involves nothing other than ANSI C.
I have a little experience with structures, having written a linked-list program for a class a couple years back, but nothing since and never used structure arrays. I have the feeling I'm missing something basic here, which is what's so frustrating. The most confusing error (and I suspect the root of most of them) is the 'state undeclared', which I just can't figure.
The errors I'm getting are:
encoder.c:11: warning: 'struct memstate' declared inside parameter list
encoder.c:11: warning: its scope is only this definition or declaration, which is probably not what you want
encoder.c: In function 'state_init':
encoder.c:22: error: two or more data types in declaration specifiers
encoder.c:25: error: 'state' undeclared (first use in this function)
encoder.c:25: error: (Each undeclared identifier is reported only once
[Code]....
Code:
Code: //Includes
#include <stdlib.h>
//------------------------------------------------------------------------------
//Creates state machine and passes back pointer to 00 state
void state_init(struct memstate* startpoint)
{
extern struct memstate
{
char output0; //output if next input is 0
[code]...
NB: I'm aware that at the moment, this code will do nothing except spin round that do-while loop. Once it's actually compiling I'll drop in some simple button-based test code so it'll check for the correct output.
I am at a loss with an assignment. I am supposed to read from a text file, with an input of something like this: alphaproleone,stroke,42 1 and Store it into an array of structures and then output it with each word/number starting on a new line. My current code prints out only the first part, and the "a" in alphaproleone is the actual number "21".
#include <iostream>
#include <string>
#include<fstream>
#include<iomanip>
using namespace std;
typedef struct drugtype {
string name, target;
int effectiveness, toxicity;
[Code]...
I have been dealing with this problem for quite some time, I've been assigned to develop a program that can store products' information within structures (the number of products is undefined). I thought I should use an array of structures, but I don't know how to declare it properly. This is what I thought would work:
struct product {
string name;
string in_stock;
float sale_cost;
int id; }
prod [n]; //n being the undefined number of products the user will register/delete/modify
I already saw an example of array of structures, but it uses a defined number.
I want to do this but do not know exactly how to do it:
Create an array of space ship objects and write a program that continually updates their positions until they all go off the screen. Assume that the size of the screen is 1024 pixels by 768 pixels.
I have begun to write a bit code but the problem is when you want to see the space ship moving step for step on the screen I do not know how to create the ship visible so you can see it is moving. Here's my code so far
Code:
#include <iostream>
using namespace std;
struct SpaceShips
{
int x_coordinate;
int y_coordinate;
[Code ......
Code:
#include<stdio.h>
#include<string.h>
typedef struct test
{
char a[5];
char b[10];
}t;
[Code] ....
In Unix (HP-UX) and Linux, the output of above program will be:
t.a=Helloworld!
Instead of the value of t.a ,i.e, "Hello" only.
Why such output? And what is the trick here to print the only value of t.a.
Why I do have this error message?
1>------ Build started: Project: TMA04, Configuration: Debug Win32 ------
1>TMA04.obj : error LNK2019: unresolved external symbol "double __cdecl getFees(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (?getFees@@YANV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) referenced in function _main
1>C:UsersEvgericDocumentsVisual Studio 2010ProjectsTMA04DebugTMA04.exe : fatal error LNK1120: 1 unresolved externals
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
