How to get the sum of rows and columns in 2 dimensional array?

[judo11]

Here's my code for adding the rows and columns. My problem is that my program displays an incorrect output.

main()
{
	int a[20][20],r,c,y,x,sum=0,rn,cn,cs=0,rs=0;
	
	cout<<"Enter number of columns : ";
	cin>>cn;
	
	cout<<"Enter number of rows : ";
	cin>>rn;
	
	cout<<"Enter "<<rn*cn<<" numbers : "<<endl;	
	
	for(r=0; r<rn; r++)
	 {
	   for(c=0; c<cn; c++)
	    {
	      cout<<">";
	 	  cin>>a[r][c];
	    }
     }
     
    cout<<"The numbers are"<<endl; 
    for(r=0; r<rn; r++)
	 {
	 	cout<<endl;
	   for(c=0; c<cn; c++)
	    {
	      cout<<a[r][c]<<"\t";
        }
     }
     
    for(r=0; r<rn; r++)//my code for getting the sum of 2d array
     {
       for(c=0; c<cn; c++)
        {
          cs=cs+a[r][c];
        }
       cout<<cs<<" ";//but the output is incorrect
     }
} 

This should be the output

Enter number of columns: 4
Enter number of rows: 3
Enter twelve numbers: 9 2 3 4 2 3 1 2 5 6 7 8
The numbers are:
9	2	3	4
2	3	1	2
5	6	7	8
Sum of number 1 column is: 16
Sum of number 2 column is: 11
Sum of number 3 column is: 11
Sum of number 4 column is: 14
Sum of number 1 row is: 18 
Sum of number 2 row is: 8
Sum of number 3 row is: 26

[cire]

You've provided the expected output, which is a good start, but you haven't provided a compilable code snippet or told us how the actual output differs from what is expected.

[judo11]

I just want to display the sum of rows and columns of 2d array

[keskiverto]

Lets use your example data. rn==3. Lets unroll the outer loop:

int cs=0;

for ( c=0; c < cn; c++ ) {
  cs = cs + a[0][c];
}
cout << cs << " "; // prints 18

for ( c=0; c < cn; c++ ) {
  cs = cs + a[1][c];
}
cout << cs << " "; // prints 26

for ( c=0; c < cn; c++ ) {
  cs = cs + a[2][c];
}
cout << cs << " "; // prints 52 

Can you yourself now see what goes wrong?

[judo11]

26 and 52 is an incorrect input it should be 18, 8 and 26

how can I correct that... please help me

[rayRase]

Disregard what I said, I was obviously wrong.

[whitenite1]

@judo11


What keskiverto is trying to tell you, is you must reset the variable 'cs', back to a '0' AFTER using the cout to display its value at the time, otherwise, all you're doing is getting the total value for ALL the rows, not individual rows.