Thread: Cannot understand this FOR statement!

Code:

char a[] = {21,12,5,7,1,9};
int size = 6;
int i,j,temp;
for(i=1;i<size;i++)
{
temp=a[i];
for(j=i; (j>0) && (a[j-1]>temp); j--)
{
a[j]=a[j-1];
}
a[j]=temp;
}

After this code is executed what values are stored in the array a?

The answer is:
{1,5,7,9,12,21}

However, I do not understand the steps undertaken to get to this solution.
IF somebody can show how they reached the FIRST array I could work from there.

I wrapped that code in a main and added in two printfs. It compiles with one warning, but works well enough to show the values. Example below. Maybe this will help you.

Code:

main()
{
char a[] = {21,12,5,7,1,9};
int size = 6;
int i,j,temp;
for(i=1;i<size;i++)
{
temp=a[i];
printf ("value of temp  is: %d \n", temp);
printf ("value of i in temp's a[i] is: %d \n", i);
for(j=i; (j>0) && (a[j-1]>temp); j--)
{
a[j]=a[j-1];
}
a[j]=temp;
}
return 0;
}

I have tried it using your method however the answers are different.

Code:

C:\MyPrograms>q1.exe
value of temp  is: 12
value of i in temp's a[i] is: 1
value of temp  is: 5
value of i in temp's a[i] is: 2
value of temp  is: 7
value of i in temp's a[i] is: 3
value of temp  is: 1
value of i in temp's a[i] is: 4
value of temp  is: 9
value of i in temp's a[i] is: 5

i will use my code to explain you. it get the same result as yours too.

Code:

main()
{
	int i,j;
	int temp;
	int number[]={21,12,5,7,1,9};
for(i=0;i<6;i++)
{
	for(j=i+1;j<6;j++)
	{
		if(number[i]>number[j])
		{
			temp=number[i];
			number[i]=number[j];
			number[j]=temp;
		}
	}
}

for(i=0;i<6;i++)
printf("%d\n",number[i]);

}