C Programming - Arrays - Discussion

well explained @Rajesh_Reddy.

printf("%d %d ",i,arr[i]);
this will give output --> 0,arr[0]
1, arr[1] ......

While,
arr[i]=++i;
printf(" %d %d\n",i,arr[0]);

This will give output --> a[1]=1
a[2]=2.....

for(i=0; i<5; i++)
printf("%d, ", arr[i]);

This for loop will ask for arr[0], which has not been assign therefore it will print garbage value.

Wonderfully explained. Thanks @Dada.

Explain please.

i=0;
while(i<5)
arr[i]=++i;
1) while(0<5) (bcoz i=0)
arr[i]=1 (bcoz ++0) --> arr[1] =1

2) while(1<5) (bcoz i=1)
arr[i]=2 (bcoz ++1) --> arr[2]=2

In the same way arr[3]=3 , arr[4]=4,
But arr[0] is not assigned any value bcoz of pre-increment, so it will give garbage value.

1) As ++ have higher precidence than =
2) 1st. ++i will be done, so i become 1
3) so arr(i) =arr(1)
4) equation is=arr(1)=1

So no value assigned to arr(0).

So its garbage value.

I think operation takes from right to left.

#include<stdio.h>
int main()
{
char s1[]="abcd",s2[]="abcd";
if(s1==s2)
{
printf("equal");
}
else
{
printf("not equal");
}
}
Can anyone please explain this?

Can anyone please explain this?

@All.

arr[i] = ++i
It means ++ has higher precedence than =.

arr[i] = ++0
arr[i] = 1
Left is incremented than we assign array value to the right side.
arr[1] = 1
and so on arr[4] = 4

Therefore we are not assigning any value for arr[0], so it takes some garbage value


Try executing the below code, hope you will understand everything in detail
#include<stdio.h>

int main()
{
int arr[5], i=0;
while(i<5)
{
printf("%d %d ",i,arr[i]);
arr[i]=++i;
printf(" %d %d\n",i,arr[0]);

}

for(i=0; i<5; i++)
printf("%d, ", arr[i]);

return 0;
}

Correct me, if I am wrong.

How the first value is a gargbage. I think output should be 1, 2, 3, 4, 5.