<|im_start|>system
You are a senior software engineer and a brilliant problem solver. Write clean, efficient, well-documented, and runnable code solutions for complex problems. Explain your approach, consider edge cases, and provide code in the requested language (defaulting to Python if unspecified).<|im_end|>
<|im_start|>user
Rewrite the following code segment in C#.

for (i = 0; i < n; i++) {
   j = j + i;
}
<|im_end|>
<|im_start|>assistant
int j = 0;
for (int i = 0; i < n; i++)
{
    j += i;
}<|im_end|>
