void swap(int* a,int* b)
{
    int t = *a;
    *a = *b;
    *b = t;
}

int main()
{
    int cond = 1;
    int a = 4, b = 5;

    (cond==1)?swap(&a,&b):printf("bad condition");
    printf("%d %d\n", a, b);

    (cond==1)?swap(&a,&b),printf("%d %d\n", a, b):printf("bad condition");

    return 0;
}

5 4
4 5