Is there any way to make a switch/case statement work for values that aren't known at runtime. I don't see why it couldn't work with variables, but my complier only seems to allow constants. I'm not picky about the method that's used but I'd perfer it would be something a little more efficient than and endless bunch of if/elses, which is the only thing I could come up with as an alternative.
Xzyx987X,
Is this what you mean?
Code:#include <stdio.h> int main(void) { /* use a character as the switch variable */ char c = '1'; unsigned int done = 0; while (!done) { switch (c) { case '1': printf("case 1\n"); c = '2'; break; case '2': printf("case 2\n"); c = '4'; break; case '3': printf("case 3 (doesn't print)\n"); c = '4'; break; case '4': printf("case 4\n"); c = '5'; break; default: done = 1; break; } } } /* similar to above except the switch variable is an integer int main(void) { unsigned int x = 1; unsigned int done = 0; while (!done) { switch (x) { case 1: printf("case 1\n"); x++; break; case 2: printf("case 2\n"); x = 4; break; case 3: printf("case 3 (doesn't print)\n"); x++; break; case 4: printf("case 4\n"); x++; break; default: done = 1; break; } } } */
No, not really. What I meant was something like this, only that worked:
Edit: One thing I'm definately aware of is that this would problbly take some dynamically generated ASM code to do, so don't tell me this is impossible just because it can't be done in pure C :P.Code:#include <stdio.h> #include <stdlib.h> int main(void) { int n = rand() % 10; int i; int numArray[4]; for(i = 0; i < 4; i++) numArray[i] = rand() % 10; switch (n) { case numArray[0]: printf("case 1\n"); break; case numArray[1]: printf("case 2\n"); break; case numArray[2]: printf("case 3\n"); break; case numArray[3]: printf("case 4\n"); break; } return 0; }
Last edited by Xzyx987X; 05-05-2004 at 12:23 PM.
You would need to use if/else type logic for this
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
An alternative approach
Code:#include <stdio.h> #include <stdlib.h> #define SIZE 10 int main(void) { int n; int i; int numArray[SIZE]; srand(time(NULL)); n = rand() % 10; for (i = 0; i < SIZE; i++) { numArray[i] = rand() % 10; } printf("Looking for %d\n", n); for (i = 0; i < SIZE; i++) { printf("Checking element %d (value:%d)\n", i, numArray[i]); if (numArray[i] == n) { break; } } if (i < SIZE) { printf("Found %d in element number %d\n", n, i); } else { printf("Failed to find it!\n"); } return(0); } /* Sample Output: Looking for 1 Checking element 0 (value:9) Checking element 1 (value:8) Checking element 2 (value:0) Checking element 3 (value:1) Found 1 in element number 3 */
When all else fails, read the instructions.
If you're posting code, use code tags: [code] /* insert code here */ [/code]
