Thread: Need some help with these two questions

1) The program should output the following: 2 3 4 1
But output this instead: 3 4 -1806417064

The

Code:

 :
    #include <stdio.h>
void swap(int *a, int *b) {
int tmp = a;
*a = *b;
*b = tmp;
}
int main() {
int array[] = {1, 2, 3, 4};
int i;
for (i = 1; i < sizeof(array) / sizeof(int) - 1; i++) {
swap( &array[i], array + i + 1);
printf("%d ", array[i]);
}
printf("%d\n", array[i]);
return 0;
}

2) The program should output the following: *H*I*
But output this instead: .U>u<.U>s<.i<>s<

The

Code:

 :
#include <stdio.h>
int main() {
char *orders = "suhsuis";
for (int i = 0, j = 0 ; i < 10; i++, j++) {
switch (orders[i]) {
case 's':
printf(".");
case 'u':
printf("%c", orders[++i] - 'a' + 'A');
break;
default:
printf(">%c<", orders[j]);
}
}
printf("\n");
return 0;

Can anyone please help me fix these codes?

For the second one re-write as a while or do/while loop.

Tim S.

from this,

Code:

(i = 1; i < sizeof(array) / sizeof(int) - 1; i++)

to this,

Code:

// either here
size_t i = 0;
( ; i < sizeof(array) / sizeof(array[0]); i++)
//or
(size_t i = 0; i < sizeof(array) / sizeof(array[0]); i++)

should be a good thing too.

run this and take a good look at all of your output to see where your 1 went to, then try to figure out what to do with lastOne to get your 1 back into your array before printing it out.

Code:

    #include <stdio.h>
int swap(int *a, int *b) {
    printf("one: a %d, b %d\n", *a,*b);
int tmp = *a;
printf("!:: a %d, b %d tmp %d\n", *a,*b, tmp);
*a = *b;
*b = tmp;

printf("a %d, b %d tmp %d\n", *a,*b, tmp);
return tmp;
}
 
int main() {
int array[] = {1, 2, 3, 4};
int lastOne = 0;

for (size_t i = 0; i < sizeof(array) / sizeof(array[0]); i++) 
printf("i=%ld %d ",i,    array[i]);
printf("\n");
size_t i = 0;
for (; i < sizeof(array) / sizeof(array[0]); i++) {

 lastOne = swap( &array[i], &array[i + 1]); 
printf("i==%ld lastOne %d\n", i,lastOne);

}
printf("outside loop\nlastOne %d i= %ld\n",lastOne, i);
 
 
for (size_t i = 0; i < sizeof(array) / sizeof(array[0]); i++) 
printf("%d ",    array[i]);
    
printf("\n");
return 0;
}

for your 2dn one you want something like this?

Code:

*U*U*à

look at your switch and what you're really doing.

Originally Posted by Hodor

You do this (or something effectively the same) in nearly every program you write and I find it extremely annoying.
What annoys me mostly is that you seem to have a compulsion to initialize variables when you declare them. At the least it's annoying, at the most it's a waste of resources if the variable doesn't need initialization (you do it anyway... why?)
The above should be written in the normal way:

Code:

size_t i;

for (i = 0; i < sizeof(array) / sizeof(array[0]); i++) {

and not how you did it and certainly not like the way you do it other times... :

Code:

size_t i = 0;

for (i = 0; i < sizeof(array) / sizeof(array[0]); i++) {

that is your idea of normal, what is your basis for comparison?

because you have no idea why the for loop is written like this,

Code:

size_t i = 0;
 
for (; i < sizeof(array) / sizeof(array[0]); i++) {

so you get extremely annoyed at me when you should be extremely annoyed at your own ignorance, and / or for having a ridge personalty trait that does not allow you to have that flexibility so you become annoyed whenever you see something that strays from what you decided to believe is a norm then project that feeling onto that other instead.

because that is a valid way to write a for loop.
1. the first part of the for loop is for what?
2. the second part of the for loop is for what?
3. the third part of the for loop is for what?

it is not my fault you do not fully understand how to use a for loop in all of the ways it can be used.
this is perfectly valid as well.

Code:

int i = 0;
for ( ; i < 10;   )
{
     i += 2;
      printf("%d\n", i)
}

What annoys me mostly is that you seem to have a compulsion to initialize variables when you declare them.

like that is a bad thing to do, your argument is not even valid. Just because you have issues with me initializing my variables when I declare them is your problem, not mine.

Variables can be initialized (assigned an initial value) in their declaration. The initializer consists of an equal sign followed by a constant expression as follows −

this is just one source.
C Variables

sorry you're so ridged

Originally Posted by Hodor

That's correct

then you need to go seek professional help for your anxiety issues to hopefully learn how to deal with your abnormal personalty traits better instead of projecting them on to me and others.

Then comes the rationalization and justification to try and elevate the stress of being wrong. in order to make something right so hopefully that feeling will go away. My suggestion stands.

Originally Posted by Hodor

Ok, I'll look into it.

I wasn't annoyed at the construction of your loops by the way. I am annoyed at the way you initialize variables when not needed (although in the above case it is needed because of the abnormal for loop)

that is called a pet peeve,
Pet Peeves – Experience Life


because your justification is not correct. that loop is not abnormal by no means, that just you trying to deflect. One could even say project your self image onto that for loop.

it does not really matter over all if one initialized the variable before or within the for loop, as long as it gets initialized before the conditional part of the for loop. That is all that matters pertaining to for loops.