CODEWITHSUNDEEP
javastringchartype-conversion
AchillesVan
AchillesVan

Reputation: 4356

implicit type casting should not works from char to String. How is this possible ?

Converting from char to String should cause the following error: This code: 

char [] arr = {'H', 'e', 'l', 'l', 'o'};
        String c = arr[1];

Error :Type mismatch: cannot convert from char to String

This code : 

char [] arr = {'H', 'e', 'l', 'l', 'o'};
String c = "";
for(char i : arr) {
    c += i;
}

Works.

Upvotes: 4

Views: 660

Answers (2)

Andreas
Andreas

Reputation: 159165

Since String is immutable, the compiler actually converts += to

c = c + i;

which compiles to

c = new StringBuilder().append(c).append(i).toString();

and StringBuilder has append overloads for all the primitive types.

Upvotes: 4

rgettman
rgettman

Reputation: 178303

The += operator, like the + operator, will perform string conversion, when one of its operands is a String and the other isn't.

The code with += will use string conversion to convert i from a char to a String for concatenation to c, a String.

The code with = will not use string conversion, because it's not in the list of acceptable conversions for assignment contexts, according to the JLS, Section 5.2.

Upvotes: 7

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