Sum the Values in an Array | C Programming Example

[@armanmazka]

These series of videos are one of the clearest, straight to the point tutorials I have ever seen for grasping the basics of C and programming.
If you are doing CS50 or any computer science course, watch this first, you'll thank me later (Week 3 Psets, I see you).
Kevin, you are an amazing teacher. Thank you for sharing your passion with us!

[@edhooper1421]

Thank you for the example for my final

[@PortfolioCourses]

You're welcome Ed! Good luck on your final. :-)

[@IceyVan]

I’m not going to fail thanks to this

[@PortfolioCourses]

I'm happy to hear that Isaiah! :-D

[@apoledev]

int SumOfArray(const int* array, int arraySize) {
int sum = 0;
while (arraySize > 0) {
arraySize --;
sum += array[arraySize];
}
return sum;
}

[@sukursukur3617]

Hello, i try to understand logic of array notation. My question is abput 2D array.
We had 2D array(or 2D set) . And we want to sum each row. When we do this, we have attained 1D array(or 1D set).
Coders use
rowTotal +=nums[i] [j]
in notation in the "for loop".
But rowTotal is 1D array, why doesnt square bracket exist?
In my mind, it should be
rowTotal[i] +=nums[i] [j]
I imagine, if something is written in nonarray formate, then it is a scaler. Namely it corresponds to only one value, 0D set.
Why isnt it like in my mind?

[@PortfolioCourses]

It depends how rowTotal is declared, you could do it either way. You could have something like:
int rowTotal = 0;
and then you could use:
rowTotal += nums[i][j];
and if it were done in a loop where j is incremented from 0 up until the length of a row (i.e. the number of columns), that should give you the sum of the row. But you could also have something like this:
int rowTotal[ROWS] = {0};
where ROWS is the number of rows. And then you could have:
rowTotal[i] += nums[i][j];
where again j is incremented from 0 up until the length of a row, and maybe i is incremented inside an outer loop that goes from 0 up until the number of rows.
So it could be done either way, it depends on how rowTotal is declared and how it is being used in the code. :-)

[@sukursukur3617]

@@PortfolioCourses first of all, thank you very much for reply.
For example
int arr[3][4]={{1,2,3,3},{4,5,6,6},{7,8,9,9}}
When we sum rows of matrix
rowTotal[3]={9,21,33} i expect matrix to turn into this 1D set.
By this reason, it sounds me it should be like this.
for(i=0,i

[@arieloh1998]

There is a way to do this program with calculate the size of the array in the function?

[@PortfolioCourses]

Not really because when we pass an array to a function we're really passing a pointer to the first element in the array. So the solution is generally to just pass the length of the array to the function as well. :-)

[@jackburton4302]

Are you able to do a similar thing with an array of floats?

[@PortfolioCourses]

The code will work the exact same way, we just need to change the type from int to float everywhere (except the loop counter variable i and the length function parameter), and then we would output the numbers with %f instead of %d. 🙂

[@jackburton4302]

@@PortfolioCourses Thank you

[@PortfolioCourses]

@@jackburton4302 You're welcome! 🙂