请教C语言问题

单步运行
(gdb) l 1
1 #include
2 main()
3 {
4 int x,y;
5 for(x=0,y=0;x+y<=10;x++,y++)
6 {
7 printf("%3d",x+y);
8 if(x%10==9){
9 printf("\n");
10 }
(gdb)
11 }
12 }
(gdb)
Line number 13 out of range; 1.c has 12 lines.
(gdb) b 3
Breakpoint 1 at 0x80483f4: file 1.c, line 3.
(gdb) run
Starting program: /home/zz/Desktop/1

Breakpoint 1, main () at 1.c:3
3 {
(gdb) n
main () at 1.c:5
5 for(x=0,y=0;x+y<=10;x++,y++)
(gdb) p x
$1 = 134513849
(gdb) p y
$2 = -1074648008
(gdb) n
7 printf("%3d",x+y);
(gdb) p x
$3 = 0
(gdb) p y
$4 = 0
(gdb) n
8 if(x%10==9){
(gdb) p x
$5 = 0
(gdb) n
5 for(x=0,y=0;x+y<=10;x++,y++)
(gdb)
7 printf("%3d",x+y);
(gdb) p x+y
$6 = 2
(gdb) n
8 if(x%10==9){
(gdb) p x
$7 = 1
(gdb) n
5 for(x=0,y=0;x+y<=10;x++,y++)
(gdb)
7 printf("%3d",x+y);
(gdb) p x+y
$8 = 4
(gdb) n
8 if(x%10==9){
(gdb) p x
$9 = 2
(gdb) n
5 for(x=0,y=0;x+y<=10;x++,y++)
(gdb)
7 printf("%3d",x+y);
(gdb) p x+y
$10 = 6
(gdb) n
8 if(x%10==9){
(gdb) p x
$11 = 3
(gdb) n
5 for(x=0,y=0;x+y<=10;x++,y++)
(gdb)
7 printf("%3d",x+y);
(gdb) p x+y
$12 = 8
(gdb) n
8 if(x%10==9){
(gdb) p x
$13 = 4
(gdb) n
5 for(x=0,y=0;x+y<=10;x++,y++)
(gdb) n
7 printf("%3d",x+y);
(gdb) p x+y
$14 = 10
(gdb) n
8 if(x%10==9){
(gdb) p x
$15 = 5
(gdb) n
5 for(x=0,y=0;x+y<=10;x++,y++)
(gdb) n
12 }
(gdb) n
0xb7ead685 in __libc_start_main () from /lib/tls/i686/cmov/libc.so.6
(gdb) n
Single stepping until exit from function __libc_start_main,
which has no line number information.
0 2 4 6 8 10
Program exited with code 014.
(gdb)

1。x％10＝＝9 判断x除以10是否遇9 \n换行
2。3％10＝＝3；
3。非0为真
4。if(x%10==9)到最后也没有执行

//欢迎在线讨论
#include
void main()
{
int x,y;
for(x=0,y=0;x+y<=10;x++,y++)
{
printf("%3d",x+y);
if(x%10==9)
printf("\n");
}
}

X怎么能%10，条件是X+Y<10,真笨？这么简单的东西还 问？不刺激刺激你？你怎么成才啊？

找电子星系工程

到底是什么问题啊