解释这个例子中的变量声明和输出

Question

I'm confused at this example:

int x = 5;
if (x==5) cout << x; // output 5
if (x==6) cout << x;
if (x=6) cout << x; // output 6
x = 0;
if (x=0) cout << x;
x = 5;
if (x-5) cout << x;
if (x-6) cout << x; // output 5

I understand first if (x==5) , but why does it output 6 at if (x=6) when x = 5, and why won't it output 0 in if(x=0)

Answer 1

if (x=6)

means not comparison, but assignment. You assign 6 to x and the return value of the expression is 6, which is not 0 so it gains true.

similar with if (x=0) The expression x=0 gains 0 so it means if(0)

Answer 2

The thing about computers is that they're extraordinarily literal. A missing semicolon, or an added character, can completely change a program's function. So you need to be just as careful as a computer when working wth programs.

As @juanchopanza alluded to, there is a difference between == and = - and you already know what it is.