c中的升序和降序

Question

I am a beginner in programming languages like c,c++ and java I really need someone to guide me on this one So the problem is: This code, I wrote on borland c++

1)

for (i = 0; i < n; i++)
{
    for (j = i; j < n; j++)
    {
        if (number[i] > number[j])
        {
        a =  number[i];
        number[i] = number[j];
        number[j] = a;
        }
    }
} 

2)

for (i = 0; i < n; i++)
{
    for (j = 0; j < n; j++)
    {
        if (number[i] > number[j])
        {
        a =  number[i];
        number[i] = number[j];
        number[j] = a;
        }
   }
} 

In the first code the logic in the inner for loop j=i will sort the numbers in ascending order,in the second code the logic in the inner for loop j=0 will sort the numbers in descending order.

Now my question is: why do the logic j=i sorts the number in ascending order and why the logic j=0 sorts the number in descending order, can someone explain the working concepts and the difference between the logic j=i and j=0?

Answer 1

What happens in the second code differently from the first is that the loop starts sorting the numbers in ascending order (just like the first code) but because the second (inner loop) compares the current number with the already sorted numbers in the beginning (which are the smallest) swaps places. Thus we end up with the largest numbers first. Look at it as if the first code is the first step of the second code: first put the numbers in order and then in descending order.