C++计算x=2,y=3,z=4计算z+=x++||y++||++z求x,y,z的值 int x=2,y=3,z=4,则表达式x+y>z&&y==...
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\u8bbex/2=y/3=z/4=k\uff0c\u6240\u4ee5x =2k\uff0cy=3k\uff0cz=4k\uff0c
\u56e0\u4e3ax+y+z=9k\u662f\u4f5c\u4e3a\u5206\u6bcd\uff0c\u8bf4\u660e9k\u22600\uff0c\u6240\u4ee5k\u22600\uff0c
\u6240\u4ee5\u539f\u5f0f=\uff082k+3k-4k\uff09/\uff082k+3k+4k\uff09
=k/9k
=1/9
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\u5148\u7b97x+y>z\uff0c\u90a3\u4e48\u663e\u71362+3>4\u6210\u7acb\uff0c\u8f93\u51fa1\u3002\u7136\u540e\u8ba1\u7b97y==z\uff0c\u90a3\u4e48\u663e\u71363==4\u4e0d\u6210\u7acb\uff0c\u6240\u4ee5\u8f93\u51fa0\u3002\u6700\u540e\u8ba1\u7b971&&0\uff0c1\u4e0e0\u80af\u5b9a\u662f0\u54af\u3002\u6240\u4ee5\u6700\u540e\u7ed3\u679c\u4e3a0.
#include<iostream>
using namespace std;
int main()
{
int x(2),y(3),z(4);
z+=x++||y++||++z;
cout<<"x="<<x<<endl<<"y="<<y<<endl<<"z="<<z<<endl;
return 0;
}
答案是 x=3 y=3 z=5
描述如下：
x++ 是非0的， 此时整个或表达式必然处理，此时C++不会看后面的y++和++z
这个叫 表达式的副作用，俗称短路
然后整个表达式的值是非0 ，所以是1 那么 z+=1 ，所以 z=5
x++是后置++ ，做完之后。自己加1
#include<iostream>
using namespace std;
int main(void)
{
int x=2,y=3,z=4;
z+=x++||y++||++z;
cout<<x<<","<<y<<","<<z<<endl;
return 0;
}
x=3
y=3
z=5
不挂科！！！
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