Interchange the contents of two variables

[glasvegas]

Alright, so I'm reading a book on C programming and this is an assignment after the first chapter.

"Two numbers are input through the keyboard into two locations C and D. Write a program to interchange the contents of C and "

I've managed to do it but to me it seems like I've done it too complicated. There should be an easier solution to doing this :P

My solution:

main()

{
   int C, D, C1, D1;

   printf("Enter a value into location C: ");
     scanf("%d", &C);
   printf("Enter a value into location D: ");
     scanf("%d", &D);

   printf("%d %d", C, D );
   printf("\n");

   C1 = C + 1;
   D1 = D + 1;

   C = D1 - 1;
   D = C1 - 1;

   printf("%d %d", C, D);

}

[tabstop]

You only need one extra value. Put one of your numbers in the extra slot, then overwrite the number you just moved out.

[quzah]

To swap A and B:

C = A (or B)
A (or B) = B (or A)
B (or A) = A (or B)

Take three cups, put a coin in each two. Only moving one coin at a time, without having more than one coin per cup, move the coins so that the starting positions of the coins are reversed.


Quzah.

[glasvegas]

Alright, so this is how I did it instead and it worked. Is that how it should be?

E = C;
C = D;
D = E;

[CommonTater]

Alright, so this is how I did it instead and it worked. Is that how it should be?

E = C;
C = D;
D = E;

Yep. But do make a habit of using more descriptive variable names in your real programs.

[ssharish2005]

And also you main function declaration looks all flat read up this int main( void ) and should return 0

ssharish

[brewbuck]

Suppose I place two coffee cups on your desk and ask you to swap them, is this task also hard to understand? The two cups can't be in the same place at the same time... It's almost as if you need some extra... space... for the exchange to occur

[quzah]

Suppose I place two coffee cups on your desk and ask you to swap them, is this task also hard to understand? The two cups can't be in the same place at the same time... It's almost as if you need some extra... space... for the exchange to occur

First, I drink cup one. Then I drink cup two. What were we doing again?


Quzah.

[CommonTater]

First, I drink cup one. Then I drink cup two. What were we doing again?

And you can even put it back when you're done with it...

[iMalc]

First, I drink cup one. Then I drink cup two. What were we doing again?

He never said there was anything in them