Summing all the numbers in a matrix revised - c++

Question

Hello I had recently asked a question about how to do the following:
Write a function that sums all the integers in a matrix of integers using the following header:
const int SIZE = 4;
double sumMatrix (const double m [] [SIZE] , int rowSize, int columnSize) ;
Write a test program that reads a 4-by-4 matrix and displays the sum of all its elements. Heres a sample run:
Enter a 4by4 matrix row by row:
1 2 3 4 [Enter]
5 6 7 8 [Enter]
9 10 11 12 [Enter]
13 14 15 16 [Enter]
Sum of the matrix is 136
I tried to use all the suggestions I could but the problem maybe that I just need to go back to the basic and learn some basic things I have skipped over, but heres what I have so far. Corrections and solutions, and help in any form would be highly appreciated.
#include <iostream>
using namespace std;
const int COLUMN_SIZE = 4;
int sum(const int a[] [COLUMN_SIZE], int rowSize)
{
int total = 0;
for (int row = 0; row < rowSize; row++)
{
for (int column = 0; column < COLUMN_SIZE; column++)
{
total += a[row][column];
}
}
return total;
}
int main()
{
int m[4][4]=
{
{1,2,3,4},
{5,6,7,8},
{9,10,11,12},
{13,14,15,16}
};
cout<< "Sum of the matrix"<< sum(m,4) << endl;
return 0;
}

Answer 1

The read function that you need will look almost the same as your print function:
void read(const int a[] [COLUMN_SIZE], int rowSize)
{
for (int row = 0; row < rowSize; row++)
{
for (int column = 0; column < COLUMN_SIZE; column++)
{
cout << "Enter number for [" << row << "][" << column << "]: ";
cin >> a[row][column];
}
}
}
(As a footnote: if you can generalise the looping and have one function that you pass 'read' or 'sum' to you're well on your way to being awesome)
edit: guess I didn't read the 'row by row' bit of the question. shrug.

Answer 2

Three years later, haha, but you can enter cols elements separating them with spaces and use enter to get elements of other row.
Improving your code. Just see and understand. A didactic program is better than a thousand words :p
#include <iostream>
using namespace std;
const int COLUMN_SIZE = 4;
int sum(const int a[] [COLUMN_SIZE], int rowSize)
{
int total = 0;
for (int row = 0; row < rowSize; row++)
{
for (int column = 0; column < COLUMN_SIZE; column++)
{
total += a[row][column];
}
}
return total;
}
void showmatrix(const int a[] [COLUMN_SIZE], int rowSize, const char *name)
{
int row_index, col_index;
cout<< name << " [" << rowSize << "][" << COLUMN_SIZE << "] =" << endl;
for(row_index = 0; row_index < rowSize; row_index++)
{
for(col_index = 0; col_index < COLUMN_SIZE; col_index++)
{
if(col_index == 0)
{
if(row_index ==0)
{
cout<< "\t /";
}
else if(row_index == rowSize - 1)
{
cout<< "\t \\";
}
else
{
cout<< "\t|";
}
}
cout<< "\t" << a[row_index][col_index];
if(col_index == 3)
{
if(row_index ==0)
{
cout<< "\t\\";
}
else if(row_index == rowSize - 1)
{
cout<< "\t/";
}
else
{
cout<< "\t |";
}
}
}
cout<< endl;
}
cout<< endl;
}
int main()
{
int m[4][4]=
{
{1,2,3,4},
{5,6,7,8},
{9,10,11,12},
{13,14,15,16}
};
int row_index, col_index;
cout<< "There is a stored matrix on that program. It is shown below: " << endl << endl;
showmatrix(m, 4, "Stored_Matrix");
cout<< "The sum of elements of that stored matrix is: "<< sum(m,4) << endl << endl;
cout<< "Now, let's enter another 4 x 4 matrix." << endl << endl;
cout<< "(Note: You can use <space> character to separate column elements or <enter>" << endl;
cout<< "key to enter a new row.)" << endl;
cout<< "(Note 2: Really, you can use both to separate each one of the 16 matrix" << endl;
cout<< "elements, but do not enter more than that or the program will do some error)." << endl << endl;
for(row_index = 0; row_index < 4; row_index++)
{
for(col_index = 0; col_index < 4; col_index++)
{
cin>> m[row_index][col_index];
}
}
cout<< endl;
cout<< "The entered matrix is below:" << endl << endl;
showmatrix(m, 4, "Entered_Matrix");
cout<< "The sum of elements of that entered matrix is: "<< sum(m,4) << endl << endl;
//only to do not close console window on Windows
cout<< "Program ended." << endl << endl << "Press something to exit.";
cin.get();
cin.get();
return 0;
}
I hope you can use it on your reborn or after developing a time machine to use that idea on your 2010 homework.
As you use C++ Builder tag for that question, you can create a new console application and copy-paste the code above overwriting generated one. Use F9 to compile and run.