两个整型变量相乘怎么判断结果是否溢出？

[hushuoqiu]

如题

[sankt]

up

[csucdl]

struct test
{
unsigned first:1;
unsigned second:1;
unsigned rst:1;
};

int main()
{
int a = 0x7fffffff;
int b = 0xffffffff;
test t;
cout<<hex<<a<<" "<<b<<endl;
t.first = (a & 0x80000000) >> 31;
t.second = (b & 0x80000000) >> 31;
t.rst = ((a + b) & 0x80000000) >> 31;
if(t.first == t.second && t.first != t.rst)
{
cout<<"over flow!"<<endl;
}
else
{
cout<<dec<<a<<" + "<<b<<" = "<<a + b<<endl;
}
return 0;
}

[cenlmmx]

这个算法有点意思