临时变量的问题

[horicon]

#include <stdio.h>
class CTemp
{
public:
int a;
public:
CTemp(CTemp& t) //Copy Ctor!
{
printf("Copy Ctor!\n");
a = t.a;
};
CTemp& operator=(CTemp& t) //Assignment Copy Ctor!
{
printf("Assignment Copy Ctor!\n");
a = t.a;
return *this;
}
CTemp(int m = 0);
virtual ~CTemp(){};
};
CTemp::CTemp(int m) //Copy Ctor!
{
printf("Construct function!\n");
a = m;
printf("a = %d\n",a);
}
CTemp Double(CTemp& ts)
{
CTemp tmp;
tmp.a = ts.a*2;
return tmp;

}
//-------------Main函数-----------------
int main()
{
CTemp tm(10),sum;
printf("\n\n");
sum = Double(tm);

printf("\n\nsum.a = %d \n",sum.a);
}




g++编译有错误：
temp_object.cpp: In function `int main()':
temp_object.cpp:39: no match for `CTemp& = CTemp' operator
temp_object.cpp:13: candidates are: CTemp& CTemp::operator=(CTemp&)
我怎么也想不明白为什么会有这种错误，求指导

[horicon]

怎么没人啊，捉急

[Tim_包]

不了解GCC，帮顶一个。

[pengzhixi]

CTemp(const CTemp& t) //Copy Ctor!
CTemp& operator=(const CTemp& t)

[至善者善之敌]

[Quote=引用 2 楼 horicon 的回复:]
把Double函数改为
CTemp Double(CTemp& ts)
{
return CTemp(ts.a*2) ;
}

错误就变成了：
temp_object.cpp: In function `CTemp Double(CTemp&)':
temp_object.cpp:34: no matching function for call to `CTemp……
[/Quote]

VS下没有错误！

[luciferisnotsatan]

[Quote=引用 6 楼 pengzhixi 的回复:]

CTemp(const CTemp& t) //Copy Ctor!
CTemp& operator=(const CTemp& t)
[/Quote]
加上const试试

[xiaolomg]

这个看下！

[horicon]

解决了，如6楼和8楼所说，要加const

[seujh]

vc6++ xp 平台，没有错误， 刚测试过，，，，，，，，，，，

结果如下：

Construct function!
a = 10
Construct function!
a = 0


Construct function!
a = 0
Copy Ctor!
Assignment Copy Ctor!


sum.a = 20
Press any key to continue

[horicon]

把Double函数改为
CTemp Double(CTemp& ts)
{
return CTemp(ts.a*2) ;
}

错误就变成了：
temp_object.cpp: In function `CTemp Double(CTemp&)':
temp_object.cpp:34: no matching function for call to `CTemp::CTemp(CTemp)'
temp_object.cpp:22: candidates are: CTemp::CTemp(int = 0)
temp_object.cpp:8: CTemp::CTemp(CTemp&)
temp_object.cpp: In function `int main()':
temp_object.cpp:41: no match for `CTemp& = CTemp' operator
temp_object.cpp:13: candidates are: CTemp& CTemp::operator=(CTemp&)

[horicon]

我在Linux下用g++编译的，就有这些错误，费解啊