code can be run/compiled here https://onlinegdb.com/ekV34x0Wr
this code will only print value 4 for all the values if tested on a 2x2 matrix
[1][2]
[3][4]
I believe its with the cout statement, I am fairly convinced it is saving the values to the matrix but, am not seeing it print correctly.
If could please tell me what I am not seeing? this syntax is very new to me, this program functions as functional programming but, is difficult once I start converting it to methods/functions.
// C Program to read a square matrix
// and print the main diagonal elements
#include <iostream>
using namespace std;
// Create a matrix based graph representation.
// It will need to support the following operations.
// Ask the user how many points there are. DONE
// Ask the user to label those points, ie "ABC", "XYZ", "C12"... DONE
// Define the matrix as a square matrix (2 dimensional array) based on the number of points, also keep an array of the labels. DONE
// Repeatedly ask the user to define edges between two points. Add these edges to the matrix. DONE
// Have a list method that will list out all of the edges in the graph.
// REFERENCE
// https://www.geeksforgeeks.org/how-to-access-elements-of-a-square-matrix/
// https://www.geeksforgeeks.org/comparison-between-adjacency-list-and-adjacency-matrix-representation-of-graph/
// https://www.cplusplus.com/reference/utility/make_pair/
// https://www.tutorialspoint.com/cplusplus-program-to-implement-adjacency-matrix
// https://stackoverflow.com/questions/2828648/how-to-pass-a-multidimensional-array-to-a-function-in-c-and-c
// https://www.techiedelight.com/pass-2d-array-function-parameter-cpp/
// https://www.tutorialspoint.com/Passing-two-dimensional-array-to-a-Cplusplus-function
// one possible implementation would be make pair to track the label for edge cout statement for user input
// Code is formatted to be best read with labels the size of 3 this is hard coded per implementation requirements.
int main()
{
// PROTOTYPE
void printMatrix(string *labelArray, int *matrix, int rowIndex, int columnIndex, int size);
int size ;
cout << "How many points would you like this to be. Points meaning -size- of matrix: ";
cin >> size;
// example 2x2 matrix
// A B
// A [][]
// B [][]
// determine size, and modulo to create matrix form
string label; // labeling convention for determining assignments
string labelArray[size]; // label containing array to track for printing and labeling purposes
int edgeYesOrNo;
int counter = 0;
cout << "Will now ask to label the points of graph matrix.\n";
int *matrix = new int[size * size]; // this is how to define a 2d array
int rowIndex; // these are to access individual elements
int columnIndex; // ^^
for(int i=0; i<size; i )
{
cout << "Enter label: "; // enter the label here to insure that there is no redundancy
cin >> label;
labelArray[i] = label;
}
// Get the square matrix
cout << "Enter 1 for edge 0 for no edge" << endl;
for (rowIndex = 0; rowIndex < size; rowIndex )
{
for (columnIndex = 0; columnIndex < size; columnIndex )
{
cout << "Is there an edge to: " << labelArray[counter] << " and " << labelArray[columnIndex] << ": ";
cin >> edgeYesOrNo;
matrix[size * size] = edgeYesOrNo;
}
counter ;
}
printMatrix(labelArray, matrix, rowIndex, columnIndex, size);
delete[] matrix;
return 0;
}
// Display the matrix
void printMatrix(string *labelArray, int *matrix, int rowIndex, int columnIndex, int size)
{
cout << "The matrix is\n" << endl;
cout << " ";
for(int i=0; i<size; i )
{
cout << labelArray[i] << " "; // To print the labels so its understandable
}
cout << endl;
for (rowIndex = 0; rowIndex < size; rowIndex )
{
cout << labelArray[rowIndex] << " ";
for (columnIndex = 0; columnIndex < size; columnIndex )
{
cout << matrix[size * size] << " ";
}
cout << endl;
}
return;
}
CodePudding user response：
What do you think these lines are going to do:
matrix[size * size] = edgeYesOrNo;
cout << matrix[size * size] << " ";
I find it far more likely you need rowIndex * size colIndex in both places.
CodePudding user response：
This is the corrected code after Joseph Larson's answer!
If people can explain to me the syntax a little more I'd be thrilled and for those that this may help, please take a look! <3
// C Program to read a square matrix
// and print the main diagonal elements
#include <iostream>
using namespace std;
// Create a matrix based graph representation.
// It will need to support the following operations.
// Ask the user how many points there are. DONE
// Ask the user to label those points, ie "ABC", "XYZ", "C12"... DONE
// Define the matrix as a square matrix (2 dimensional array) based on the number of points, also keep an array of the labels. DONE
// Repeatedly ask the user to define edges between two points. Add these edges to the matrix. DONE
// Have a list method that will list out all of the edges in the graph.
// REFERENCE
// https://www.geeksforgeeks.org/how-to-access-elements-of-a-square-matrix/
// https://www.geeksforgeeks.org/comparison-between-adjacency-list-and-adjacency-matrix-representation-of-graph/
// https://www.cplusplus.com/reference/utility/make_pair/
// https://www.tutorialspoint.com/cplusplus-program-to-implement-adjacency-matrix
// https://stackoverflow.com/questions/2828648/how-to-pass-a-multidimensional-array-to-a-function-in-c-and-c
// https://www.techiedelight.com/pass-2d-array-function-parameter-cpp/
// https://www.tutorialspoint.com/Passing-two-dimensional-array-to-a-Cplusplus-function
// one possible implementation would be make pair to track the label for edge cout statement for user input
// Code is formatted to be best read with labels the size of 3 this is hard coded per implementation requirements.
int main()
{
// PROTOTYPE
void printMatrix(string *labelArray, int *matrix, int rowIndex, int columnIndex, int size);
int size ;
cout << "How many points would you like this to be. Points meaning -size- of matrix: ";
cin >> size;
// example 2x2 matrix
// A B
// A [][]
// B [][]
// determine size, and modulo to create matrix form
string label; // labeling convention for determining assignments
string labelArray[size]; // label containing array to track for printing and labeling purposes
int edgeYesOrNo;
int counter = 0;
cout << "Will now ask to label the points of graph matrix.\n";
int *matrix = new int[size * size]; // this is how to define a 2d array
int rowIndex; // these are to access individual elements
int columnIndex; // ^^
for(int i=0; i<size; i )
{
cout << "Enter label: "; // enter the label here to insure that there is no redundancy
cin >> label;
labelArray[i] = label;
}
// Get the square matrix
cout << "Enter 1 for edge 0 for no edge" << endl;
for (rowIndex = 0; rowIndex < size; rowIndex )
{
for (columnIndex = 0; columnIndex < size; columnIndex )
{
cout << "Is there an edge to: " << labelArray[counter] << " and " << labelArray[columnIndex] << ": ";
cin >> edgeYesOrNo;
matrix[rowIndex * size columnIndex] = edgeYesOrNo;
}
counter ;
}
printMatrix(labelArray, matrix, rowIndex, columnIndex, size);
delete[] matrix;
return 0;
}
// Display the matrix
void printMatrix(string *labelArray, int *matrix, int rowIndex, int columnIndex, int size)
{
cout << "The matrix is\n" << endl;
cout << " ";
for(int i=0; i<size; i )
{
cout << labelArray[i] << " "; // To print the labels so its understandable
}
cout << endl;
for (rowIndex = 0; rowIndex < size; rowIndex )
{
cout << labelArray[rowIndex] << " ";
for (columnIndex = 0; columnIndex < size; columnIndex )
{
cout << matrix[rowIndex * size columnIndex] << " ";
}
cout << endl;
}
return;
}