单项选择题

下列程序输出的结果是( )。 #include<stdio.h> fun1(char a,char b){char c;c=a;a=b;b=c;} fun2(char*a,char b){char c;c=*a;*a=b;b=c;} fun3(char*a,char*b){char c;c=*a;*a=*b;*b=c;} void main() { char a,b; a=’A’;b=’B’;fun1(a,b);putchar(a);putchar(b); a=’A’;b=’B’;fun2(&a,b);putchar(a);putchar(b); a=’A’;b=’B’;fun3(&a,&b);putchar(a);putchar(b); putchar(’\n’); }

A.BABBAB
B.ABBBBA
C.ABBABA
D.ABABBA