2D Arrays(Manipulation)

[Leemanphltroy]

Hi
I'am new to programming and i need help concerning 2D arrays. If i read in data values from a file and stored these data into a 2D array. How can i manipulate the datas stored within this array?? Say...

My Array is;

float num[3][2];

and the file data is;

intergers1 integers 2
1 2
3 4
5 6
Now the manipulation is, i want to sum up all values under heading (integers2) and print out the sum.

[int main]

The more obvious way would be to introduce two loops to read and write the array.

for (int i = 0; i<3;i++)
    {
      for (int j= 0; j<2; j++)
         { 2DArray[i][j] = whatever;
         }
    }

This way you can iterate through the whole array and address every element seperately.

A more elegent way I think is to iterate throught the array this way:

int 2DArray [3][2] = {0];
int* p2DArray = 2DArray;

for (int i = 0; i< 6; i ++)
{ *(p2DArray + i) = whatever;
}

I hope I have pointed you into the right direction.

int main

[jmc]

To write your hole array you could also use the relatively fast function memset

[mahlerfive]

To add up the numbers you want, just think of how the indices change as you move through the array. You know that the first dimension index has to increase by 1 each time, and that the second dimension index is always 1 since you always want the 2nd value. So we can create a single loop to sum these numbers:
[code=c++]
sum = 0;
for( int i = 0; i < 3; i++ ) {
sum += num[i][1];
}
[/code]