how to use logical operator directly into the user defined variables

Question

#include <iostream>
using namespace std;

int main() {
// your code goes here
int x=1;
int y;
y=x&&10;
cout<<y;
return 0;
}

The output is 1.

How is the value stored in y? What is the operation of &&? Please explain.

Have you consulted a reference or a [good book](http://stackoverflow.com/q/388242/1782465)? What has this told you, and what is still unclear? Please add such details to your question. — Angew is no longer proud of SO, Oct 15 '14 at 14:33

score 2 · Answer 1 · answered Oct 15 '14 at 14:30

This operation

y=x&&10;

is evaluated as:

x && 10
1 (int) && 10 (int)
true && true        // Note any non-zero integer will be evaluated to true
true

Therefore

y = true

But y is an int, so then there is an implicit conversion from bool back to int, which results in y being 1.

score 2 · Answer 2 · answered Oct 15 '14 at 14:39

If you write "a && b" then both of the variables a and b must equate to true, for the result of the expression to return true, otherwise false will be the result.

For integers, all values which are not zero are considered true. Both of your variables are non-zero so your expression returns true.

When a boolean is stored into an integer, true is expressed as 1 whilst false is expressed as zero.

This is why your application outputs 1.

score 1 · Accepted Answer · answered Oct 15 '14 at 14:36

1

y=0 only if you put 0 instead of 10 or assign 0 to x.
if the values of left hand operand and right hand operand both are non-zero y=1 as both represents true.
if one of the operand is 0 then y=0 as 0 represents false.

answered Oct 15 '14 at 14:36

MD. Khairul Basar

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how to use logical operator directly into the user defined variables

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