#include double foo(int a, char *p); main() { double x; int i; char c = 'a'; for (i = 0; i < 4; i++) x = foo(i, &c); printf("one:%c two:%.1lf three:%d\n", c, x, i); } double foo(int a, char *p) { double d; printf("%c ", *p); switch (*p) { case 'a': *p = 'c'; d = a * 0.5; break; case 'b': *p = 'a'; d = a * 1.5; break; case 'c': *p = 'b'; d = a * 0.1; break; default: d = 1.7; } printf("%.1lf\n", d); return d; }