在使用cout对象时要注意的一个小问题

 1 #include <iostream>
 2 
 3 using std::cout;
 4 using std::endl;
 5 
 6 // 交换x和y的值并返回两者中较大的值 
 7 int swap(int &x, int &y);
 8 
 9 int main()
10 {
11     int x = 1, y = 2;
12     cout << swap(x, y) << " " << x << " " << y << endl;
13     
14     return 0;
15 }
16 
17 int swap(int &x, int &y)
18 {
19     int temp = x;
20     x = y;
21     y = temp;
22     
23     return (x > y ? x : y);
24 }

 1    0x004016cd <+29>:    call   0x409810 <__main>
 2    0x004016d2 <+34>:    movl   $0x1,-0x1c(%ebp)
 3    0x004016d9 <+41>:    movl   $0x2,-0x20(%ebp)
 4    0x004016e0 <+48>:    mov    -0x20(%ebp),%ebx
 5    0x004016e3 <+51>:    mov    -0x1c(%ebp),%esi
 6    0x004016e6 <+54>:    lea    -0x20(%ebp),%eax
 7    0x004016e9 <+57>:    mov    %eax,0x4(%esp)
 8    0x004016ed <+61>:    lea    -0x1c(%ebp),%eax
 9    0x004016f0 <+64>:    mov    %eax,(%esp)
10    0x004016f3 <+67>:    call   0x40175c <swap(int&, int&)>
11    0x004016f8 <+72>:    mov    %eax,(%esp)
12    0x004016fb <+75>:    mov    $0x464fa0,%ecx
13    0x00401700 <+80>:    call   0x438df0 <_ZNSolsEi>
14    0x00401705 <+85>:    sub    $0x4,%esp
15    0x00401708 <+88>:    movl   $0x466064,0x4(%esp)
16    0x00401710 <+96>:    mov    %eax,(%esp)
17    0x00401713 <+99>:    call   0x458000 <_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc>
18    0x00401718 <+104>:    mov    %esi,(%esp)
19    0x0040171b <+107>:    mov    %eax,%ecx
20    0x0040171d <+109>:    call   0x438df0 <_ZNSolsEi>
21    0x00401722 <+114>:    sub    $0x4,%esp
22    0x00401725 <+117>:    movl   $0x466064,0x4(%esp)
23    0x0040172d <+125>:    mov    %eax,(%esp)
24    0x00401730 <+128>:    call   0x458000 <_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc>
25    0x00401735 <+133>:    mov    %ebx,(%esp)
26    0x00401738 <+136>:    mov    %eax,%ecx
27    0x0040173a <+138>:    call   0x438df0 <_ZNSolsEi>
28    0x0040173f <+143>:    sub    $0x4,%esp
29    0x00401742 <+146>:    mov    $0x0,%eax
30    0x00401747 <+151>:    jmp    0x401751 <main()+161>
31    0x00401749 <+153>:    mov    %eax,(%esp)
32    0x0040174c <+156>:    call   0x40c570 <_Unwind_Resume>
33    0x00401751 <+161>:    lea    -0xc(%ebp),%esp
34    0x00401754 <+164>:    pop    %ecx
35    0x00401755 <+165>:    pop    %ebx
36    0x00401756 <+166>:    pop    %esi
37    0x00401757 <+167>:    pop    %ebp
38    0x00401758 <+168>:    lea    -0x4(%ecx),%esp
39    0x0040175b <+171>:    ret