#include #include void echanger1 (int x, int y) { int temp; temp = x; x = y; y = temp; } void echanger2 (int *px, int *py) { int temp; temp = *px; *px = *py; *py = temp; } int main (void) { int a = 1, b = 2; printf ("a= %d: b= %d\n", a, b); echanger1 (a, b); printf ("a= %d: b= %d\n", a, b); echanger2 (&a, &b); printf ("a= %d: b= %d\n", a, b); return EXIT_SUCCESS; }