*How 14 and 20 came on the output can anyone explain?*

Question

//*How 14 and 20 came on the output can anyone explain?*
#include <stdio.h>
main() {
int i, j, k, x = 0;
for (i = 0; i < 5; ++i) {
for (j = 0; j < i; ++j) {
k = (i + j - 1);
if (k % 2 == 0)
x += k;
else if (k % 3 == 0)
x += k - 2;
printf("%d\n", x);
}
}
printf("\nx = %d", x);
}

/*output:
0
0
2
4
5
9
10
14
14
20

x = 20Press any key to continue . .
*/

Answer 1

To further understand what is going on.. let make some minor adjustment to the code as below:

#include <stdio.h>
int main() {
int i, j, k, x = 0;
for (i = 0; i < 5; ++i) {
for (j = 0; j < i; ++j) {
k = (i + j - 1);
if (k % 2 == 0)
x += k;
else if (k % 3 == 0)
x += k - 2;
printf("i=%d j=%d k=%d x=%d\n", i, j, k,x);
}
}
printf("\nx = %d", x);
}

so we will get output such as below:

i=1 j=0 k=0 x=0
i=2 j=0 k=1 x=0
i=2 j=1 k=2 x=2
i=3 j=0 k=2 x=4
i=3 j=1 k=3 x=5
i=3 j=2 k=4 x=9
i=4 j=0 k=3 x=10
i=4 j=1 k=4 x=14
i=4 j=2 k=5 x=14
i=4 j=3 k=6 x=20

x = 20

So, I assume you want to know how the 2 last output come to be. The reason is, at i=4 and j=2, our k is 5 which means that there is no adjustment made to x because both if and else if statement return false.

let k = 5,
k % 2 == 0 will return false
k % 3 == 0 will return false

Then in the next iteration when i=4, j=3, our x become 20 because it pass if statement.

let k = 6,
k % 2 == 0 will return true
k % 3 == 0 will return true

since we wrote our code using if and else if instead of 2 separate if statement, it simply ignore the else if k%3 since the k%2 is already true. That is why it return 20 (14 + k where k is 6)

Answer 2

Let look back at the part of code that responsible to adjust the value of x
```
if (k % 2 == 0)
x += k;
else if (k % 3 == 0)
x += k - 2;
```

As you can see, if k%2==0, then our x will increase as much as k but if k%3==0, x will increase as much as k-2.

But since k=5, both k%2==0 and k%3==0 is false. Which mean that there is no changes make to x.

Since,
5%2 = 1
5%3 = 2

Therefore

k%2==0 is false
and
k%3==0 is also false

That is why 14 appear twice. Because there is no changes to x when k=5

Answer 3

I am really appreciate your precious answer. Thanks a lot!

Can you please explain how 14 came twice on the output. I am confused about
it.

Since, when i=4, j=1, K=4, x=10+4=14 ( Totally clear )
But, when i=4, j=2, k=5, x= ?

both of the condition is false here so what will be
the output here? and how?

Answer 4

Oh now I am fully clear about the following code. Once again thanks for giving your precious time to solve my question.