C multidimensional arrays

Hey, I'm naturally a vb.net programmer and I'm lost with C's syntax. I'm trying to create an application where the user inputs some values and then have it run some statistical analysis, but I can't get past the user input part.

Code:

#include <stdio.h>
#include <stdafx.h>
#define N 25
int main(void)

{
    double numberarray[N]];
	int row, col;
	for (row = 0; row < N; row++)
			for (col = 0; col < N; col++)
					if (row == col)
						scanf("%d", numberarray[row][col]);
					else
						scanf("%d", numberarray[row][col]);
    return 0;
}

Any help will be greatly appreciated, thank you!
-sin2win

Code:

double numberarray[N]];  /* missing the 2nd dimension */

Code:

{
    double gradearray[N][N];
    int row =0 , col = 0, i = 1, factor = 1;
 
    printf("Enter max error: ");
 for (row = 0; row < N; row++)
	 for (col = 0; col < N; col++)
	 {
		 if (row == col)
		 {
			 gradearray[row][col]=getchar();
		 }
		 else
		 {
			 gradearray[row][col]=getchar();
		 }
	 }
	 for (row = 0; row < N; row++)
	 for (col = 0; col < N; col++)
	 {
		 if (row == col)
		 {
			 printf("%d", gradearray[row][col]);
		 }
		 else
		 {
			 printf("%d", gradearray[row][col]);
		 }
	 }

This is what I have, it allows me to enter the values for the array but it doesn't seem to be storying them.

I am trying to loop through the array one row at a time and input the values for each column in a row.

You're on the right track. A simple example:

Code:

 for (row = 0; row < N; row++)  {
    for (col = 0; col < N; col++)  {
   	 scanf("%d", &gradearray[row][col]);
	 printf("%3d  ", gradearray[row][col]);
   }
}

The ampersand '&', gives scanf() the address of the variable, so it can actually change it. Note how printf() doesn't need that address, since it won't be changing anything.

In general, it's a good idea to get all your input done first, then work on it in another pair of nested loops.

Trying to input data into a 2D array, and also do some computational work, will make things very prone to errors.

Thanks for your help, I got it to where it properly allows the user to enter the values into the array, now I need to have each row summed.

Code:

st1ttl = (gradearray[0][0] + gradearray[0][1] + gradearray[0][2] + gradearray[0][3] + gradearray[0][4]);
printf("\t", st1ttl, "\n");

This code apparently isn't saving any value to st1tll....Is there a simpler function to sum the values in a row of the array?

Originally Posted by sin2win

Thanks for your help, I got it to where it properly allows the user to enter the values into the array, now I need to have each row summed.

Code:

st1ttl = (gradearray[0][0] + gradearray[0][1] + gradearray[0][2] + gradearray[0][3] + gradearray[0][4]);
printf("\t", st1ttl, "\n");

This code apparently isn't saving any value to st1tll....Is there a simpler function to sum the values in a row of the array?

The problem is your printf() call is mal-formed. You need to tell printf() what data type you want printed. Perhaps %d for integers?

printf("\t %d", st1ttl);

There is no function to sum up a row. You went about it the hard way. Easy way is to use a nested loop:

Code:

for(j = 0; j < NumColumnsInEachRow; j++)
  rowTotal += gradearray[row][j];

Just remember to use your totals and such, and to reset them to zero, before the next loop starts. That should work.