void swap (char *x,char *y) { char *t; t=x; x=y; y=t; } void main() { char *s1="abc",*s2="123"; swa

void swap (char *x,char *y) { char *t; t=x; x=y; y=t; } void main() { char *s1="abc",*s2="123"; swa

void swap (char *x,char *y) { char t; t=*x; *x=*y; *y=t; }
x和y,是地址,*x和*y才是char的值,要交换的是char的值