Quick question... Structs & Arrays.

This is a discussion on Quick question... Structs & Arrays. within the C++ Programming forums, part of the General Programming Boards category; Hi everyone. I am working on making a program that deals with household surveys. I am still learning C++ and ...

  1. #1
    Registered User hottiefee's Avatar
    Join Date
    Oct 2010
    Location
    TN, USA
    Posts
    32

    Unhappy Quick question... Structs & Arrays.

    Hi everyone. I am working on making a program that deals with household surveys. I am still learning C++ and my first time dealing with more than one array. Here is the problem:
    Write a program to read these survey results. Each record contains data for one household, including a 4-digit integer id number, the annual income, and number of household members. Max of 25 households. Write a program to read the results into 3 arrays.
    It sounds to me like I need to use a struct.. but I'm not sure. Here is how I think it should be written...

    Code:
    #define MAX_SIZE 25
    #include 
    struct household{
    	int id[size];
    	int income[size];
    	int members[size];
    };
    void readStruct(household&, int&);
    void displayStruct(household stuhousehold, int);
    int main(){
    	int size = 0;
    
    	struct household value;
    	
    	household info;
    	readStruct(household, size);
    	displayStruct(household stuhousehold, size);
    
    	return 0;
    }
    
    void readStruct(household& oneHouse, int& size){
    	int i = 0;
    	cout << "Enter the four-digit integer identification number: ";
    	cin >> household id;
    	cout << "Enter the annual household income: ";
    	cin >> household income;
    	cout << "Enter the number of household members: ";
    	cin >> household members;
    	
    	while(members > 0 && i < MAX_SIZE)                       // I was trying to count # of households with i.
    
    }
    
    void displayStruct(household stuhousehold, int n){
    	cout << setw(28) << "Identification Number" << setw(28) << "Annual Income" << setw(28) << "Household Members" << endl;
    	
    	for(int i=0; i<n; i++)
    		for(int j=0; j<n; j++)
    			for(int k=0; k<n; k++)
    				cout << setw(28) << stuhousehold.id[i] << setw(28) << stuhousehold.income[j] << setw(28) << stuhousehold.members[k] << endl;
    }
    I think I messed up. I'm kind of confused so if anyone knows of a good website or something to help explain arrays and structs, let me know. Thank you.

  2. #2
    -bleh-
    Join Date
    Aug 2010
    Location
    somewhere in this universe
    Posts
    452
    This is not really a struct problem because of the requirement of reading into 3 arrays. Just move
    Code:
    	int id[size]; <--- 1st array
    	int income[size]; <--- 2nd array
    	int members[size]; <--- 3rd array
    into your main() function to make your life easier.

    if you want to use struct,
    Code:
    struct household{
    	int id;
    	int income;
    	int members;
    };
    
    int main()
    {
       household array[size];  <------- an array of 25 element of type household. 
    }
    then your read struct function would be come
    Code:
    void readStruct(household & struct_array, int& size){
    int i = 0;
    // use a while-loop, or do-while loop. 
    do{
    	
    	cout << "Enter the four-digit integer identification number: ";
    	cin >> struct_array[i].id; // reading into the member variable "id" of the i-th element of the array of type household. 
         .... etc...
             ++i ; <--- need to increment i
    }	while(i < MAX_SIZE)                       // I was trying to count # of households with i.
    
    }
    Last edited by nimitzhunter; 02-10-2011 at 12:57 AM.
    "All that we see or seem
    Is but a dream within a dream." - Poe

  3. #3
    Registered User hottiefee's Avatar
    Join Date
    Oct 2010
    Location
    TN, USA
    Posts
    32
    Thank you. I'll try that.

  4. #4
    Registered User hottiefee's Avatar
    Join Date
    Oct 2010
    Location
    TN, USA
    Posts
    32

    Question

    Okay. Here is what I have.
    Code:
    #include<iostream>
    #include<iomanip>
    #define MAX_SIZE 25
    
    void getArray1(int[], int&, int&);
    void getArray2(int[], int&);
    void getArray3(int[], int&);
    void displayTable(int[], int[], int[], int);
    
    using namespace std;
    int main(){
    	int list1[MAX_SIZE];
    	int list2[MAX_SIZE];
    	int list3[MAX_SIZE];
    	int size1, size2, size3;
    	int value1;
    
    	do{
    	getArray1(list1, size1, value1);			// 1 is 4-digit ID number
    	getArray2(list2, size2);					// 2 is Annual income
    	getArray3(list3, size3);					// 3 is Number of household members
    	}
    	while(value1 >= 0 && size1 < MAX_SIZE);
    
    	displayTable(list1, list2, list3, size1);
    
    	return 0;
    }
    
    
    void getArray1(int id[], int& size1, int& value){
    	int i = 0;
    
    	cout << "Enter the four-digit integer identification number (-1 to stop): ";
    	cin >> value;
    
    	id[i] = value;
    	i++;
    	size1 = i;
    }
    void getArray2(int income[], int& size2){
    	int j = 0;
    	int value;
    
    	cout << "Enter the annual household income: ";
    	cin >> value;
    
    	income[j] = value;
    	j++;
    	size2 = j;
    }
    void getArray3(int members[], int& size3){
    	int k = 0;
    	int value;
    
    	cout << "Enter the number of household members: ";
    	cin >> value;
    
    	members[k] = value;
    	k++;
    	size3 = k;
    }
    
    void displayTable(int id[], int income[], int members[], int size){
    	cout << "Number of households: " << size << endl;
    	cout << endl;
    	cout << setw(20) << "ID Number" << setw(20) << "Annual Income" << setw(20) << "Household Members" << endl;
    	for(int i=0; i < size; i++)
    		cout << setw(20) << id[i] << setw(20) << income[i] << setw(20) << members[i] << endl;
    }
    When I run this, it doesnt display more than the last set of data (id, income, members) with -1 as the id..

  5. #5
    -bleh-
    Join Date
    Aug 2010
    Location
    somewhere in this universe
    Posts
    452
    You got your iteration incorrectly. You are iterating in main() instead of in the the function getArray. So for every iteration, you keep calling income[0], id[0] and members[0], thus your answer is just one output of -1 in the end. Well, one way to remedy that is to use static variable.
    Code:
    static int k = 0 ;
    But why do that when you can just use one function that take in all 3 arrays, and iterate over them inside the function?

    Code:
    void getArray(int id[],int income[], int members[])
    {
    // HERE IS WHERE YOU USE THE USE THE LOOP, not in main()
    // don't need to pass in the size argument since you already define MAX_SIZE
    //whatever-loop you want to do here: for, do-while, while. your choice. 
    //If you use do-while or while remember to declare int i = 0 outside of the loop and increment it inside the loop. 
    for( int i = 0 ; i < MAX_SIZE ; ++i)
    {
       cout << "Enter the four-digit integer identification number";
       cin >> id[i];
       cout << "Enter the annual household income: ";
       cin >> income[i];
      ///etc.....
    }
    }
    Last edited by nimitzhunter; 02-10-2011 at 01:05 AM.
    "All that we see or seem
    Is but a dream within a dream." - Poe

  6. #6
    Registered User hottiefee's Avatar
    Join Date
    Oct 2010
    Location
    TN, USA
    Posts
    32
    Thanks! I seen that was my problem and I've been wondering how to fix it. I'm working on it now.

  7. #7
    Registered User hottiefee's Avatar
    Join Date
    Oct 2010
    Location
    TN, USA
    Posts
    32
    It worked! (using one function to take all 3 arrays). Thanks so much. Have a good day.

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. Comparing Arrays question
    By taugust7 in forum C++ Programming
    Replies: 36
    Last Post: 04-14-2009, 12:29 PM
  2. Quick question about types...
    By Elysia in forum C++ Programming
    Replies: 32
    Last Post: 12-07-2008, 04:39 AM
  3. Very quick question about dynamic arrays.
    By Lawn Gnomusrex in forum C++ Programming
    Replies: 4
    Last Post: 11-13-2008, 02:22 PM
  4. Quick question arrays/pointers
    By liljp617 in forum C Programming
    Replies: 6
    Last Post: 10-02-2008, 12:11 PM
  5. Quick question: exit();
    By Cheeze-It in forum C Programming
    Replies: 6
    Last Post: 08-15-2001, 05:46 PM

Tags for this Thread


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21