Need enum type casting explanation in c++

Question

Following is my test code

#include "test.h"
#include <iostream>

typedef enum{
    A = 0,
    B
 } testEnum;

int main()
{
    testEnum e = static_cast<testEnum>(3);
    printf("My enum Value : %d\n", (int)e);
    int stop = 0;
}

programs out is My enum Value : 3 Now in program i am type casting number 3 into enum and then printing it as int. My guess way this should give error or garbage value or 1 (as enum highest value). But out put is 3. Can somebody what are the rules and how it works. Thank you!

score 2 · Answer 1 · answered Feb 12 '15 at 12:28

2

n3376 5.2.9/10

A value of integral or enumeration type can be explicitly converted to an enumeration type. The value is unchanged if the original value is within the range of the enumeration values (7.2). Otherwise, the resulting value is unspecified (and might not be in that range).

answered Feb 12 '15 at 12:28

ForEveR

55,233
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thank i got the point +1 for standard provided. – DigviJay Patil Feb 12 '15 at 12:31

score 1 · Accepted Answer · answered Feb 12 '15 at 12:26

1

Enum in an integral type (number). By type casting, you tell the compiler that you know the value is correct but there is no conversion occuring. You need to check the values/range yourself.

Btw. it actually gives a garbage value: 3

answered Feb 12 '15 at 12:26

StenSoft

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3 is garbage value how can you just explain to me +1 for proper answer. – DigviJay Patil Feb 12 '15 at 12:28
It's a garbage value because it doesn't mean anything in context. – TartanLlama Feb 12 '15 at 12:29

Need enum type casting explanation in c++

2 Answers2