CODEWITHSUNDEEP
c++castinginteger-arithmetic
Anonymous
Anonymous

Reputation: 9

Expression inside a static cast

I wrote a code like this :

#include<iostream>
using namespace std;

int main()
{
    cout<<static_cast<float>(5/9)*9;
    cout<<static_cast<float>(5)/9*9;
    return 0;
}

Expected output :55

Original output :05

Why the first static cast statement turned to 0 ?

Upvotes: 1

Views: 155

Answers (1)

Vlad from Moscow
Vlad from Moscow

Reputation: 311068

In this sub-expression 

(5/9)

of this statement

cout<<static_cast<float>(5/9)*9;

there is used the integer arithmetic. The result of the sub-expression is 0. This result is converted to the type float.

static_cast<float>( 0 )

That is the casting is applied to the primary sub-expression in parentheses after its evaluation.

In the second statement

cout<<static_cast<float>(5)/9*9;

that is in fact equivalent to

cout<< 5.0f/9*9;

in the sub-expression

static_cast<float>(5)/9

or that is the same

5.0f / 9

there is used the arithmetic with floating numbers and the result is not equal to 0.

Upvotes: 5

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