I want to make a circular counter in C programming. First variable can store value from 0-3. Second variable asks the value from user (from 0-3). Third variable asks user to move either left or right
If third variable is left the second variable should move left:
3->2 2->1 1->0 0->3 Similarly if third variable is right the second variable should move right:
0->1 1->2 2->3 3->0 2 Answers
#include <stdio.h> int main(void) { int max = 3, num, i; num = 0; for (i = 0; i < 10; i++) { printf("%d\n", num); num = (num + 1) % (max + 1); } puts("--"); num = max; for (i = 0; i < 10; i++) { printf("%d\n", num); num = (max - -num) % (max + 1); } return 0; } Output:
0 1 2 3 0 1 2 3 0 1 -- 3 2 1 0 3 2 1 0 3 2 If you wrap at a power of two, then this technique will work.
#include <stdio.h> typedef struct { unsigned int x : 2; /* Holds up to 4 values */ } SmallInt; int main() { SmallInt up = {0}; SmallInt down = {0}; for (int z = 0; z < 10; z++) { printf("%d %d\n", up.x, down.x); up.x++; down.x--; } return 0; } 
