fun(int x) {int p; if(x==0||x==1) return(3); p=x-fun(x-=2); return p; } main() { printf("%d\n",fun(fun(int x){int p;if(x==0||x==1) return(3);p=x-fun(x-=2);return p;}main(){ printf("%d\n",fun(7));}求输出结果,

fun(int x) {int p; if(x==0||x==1) return(3); p=x-fun(x-=2); return p; } main() { printf("%d\n",fun(fun(int x){int p;if(x==0||x==1) return(3);p=x-fun(x-=2);return p;}main(){ printf("%d\n",fun(7));}求输出结果,
fun(int x) {int p; if(x==0||x==1) return(3); p=x-fun(x-=2); return p; } main() { printf("%d\n",fun(
fun(int x)
{int p;
if(x==0||x==1) return(3);
p=x-fun(x-=2);
return p;
}
main()
{ printf("%d\n",fun(7));}
求输出结果,

fun(int x) {int p; if(x==0||x==1) return(3); p=x-fun(x-=2); return p; } main() { printf("%d\n",fun(fun(int x){int p;if(x==0||x==1) return(3);p=x-fun(x-=2);return p;}main(){ printf("%d\n",fun(7));}求输出结果,
fun(7)
p=x-fun(x-=2)此时x=5;
故p=5-fun(5);
同理
fun(5)
p=x-fun(x-=2)此时x=3
故p=3-fun(3);
fun（3）
p=x-fun(x-=2)此时x=1
故p=1-fun(1)=-2
所以fun(7)=5-(3-(1-fun(1)))=0