Array help

[rick13mul]

I'm doing some practice hw and I'm stuck on two of them, anyone care to help?


1. A two dimensional array has 5 rows and 5 columns. Assume the array has been initialized. Write C code to sum the first and third columns. Write a C statement to sum the diagonal elements from bottom left to top right.

2. For the double array z, write the code to sum the elements 7 through 16 of the array and print the resultn. Assume: double z and that the array has already been initialized.

[laserlight]

What have you tried?

[vart]

I'm doing some practice hw

If you really doing it - you have some code
at least

int main(void)
{
   return 0;
}

Show what you have and explain what are the problems you cannot resolve

[rick13mul]

its all hand written hw, i understand that for a two dimensional array its [][] but i do not know how to sum the separate columns without summing the entire program

[laserlight]

its all hand written hw

I have the answer, but its on a piece of paper. You can come over to my house and collect it

Basically, type out what you have written, test it, and then ask for help if it does not work. Explain how does it not work, and post the code you tested.

[vart]

for(x=0;x<5;x++)
   sum += arr[x][3];

something like that

[rick13mul]

Well for the second one i have


int I, x[20], total=0;
For (I=6; I<=15, I++)
total=total+x[I];
printf ("%1d/n",x[I])

[sillyman]

#include <stdio.h>

int main(void)
{
        int b, c;    
        float a[5][5];     

        //'init array a
        for ( c=0; c < 5; c++)
        {       
                for ( b=0; b<5; b++)
                {
                        a[b][c] = 1;
                }
        }
 

        return 0;
}

what else do you have coded?

[Elysia]

Use code tags, please.
Secondly, x is not initialized. Even though it says assume, you can't run this code. If you already have some code where it's initialized, that's fine.

total=total+x[i];

Is the same as

total += x[i];

printf ("%1d/n",x[i])

%1 is not a format specifier. If you want to pad with 0s, perhaps something like

printf ("%0.1d\n",x[i])

NOTE: Unsure on this one.

Also, '/n' is not what you expect.
It's '\n'. Forget Linux-type paths. '\n' is not a path, it's a special char and special chars always begins with \.