CODEWITHSUNDEEP
javacexceptionformatformat-specifiers
asad
asad

Reputation: 316

Inconsistency in relationship between Java and C

Please forgive me if my question seems pretty noobish. This is my first question over here.

I am having a simple query in my mind. Java language has been implemented using C and C++.

My question is

In C language,the formatting behaviour of C is undefined for using different modifiers than the given datatype.

int c=10;
printf("%f",c);    // unspecified behaviour

Whereas in Java, if we use the similar concept to print the number using different format specifier, we get an IllegalFormatConversionExceptoion.

Exception Detail :-

Exception in thread "main" java.util.IllegalFormatConversionException: f != java.lang.Integer

My question is :-

Why so difference between Java and C though Java is derived from C!

Please clear my doubt. I'll be thankful to you geniuses...

Upvotes: 1

Views: 88

Answers (2)

Peter Lawrey
Peter Lawrey

Reputation: 533870

The printf in Java is inspired by the same method in C but works completely differently. If you give it a BigDecimal for example it will print it even though C doesn't have a BigDecimal.

In short, just because Java is similar to C, doesn't mean it use the same underlying functions. In most cases, Java has it's own implementations to ensure;

  • defined behaviour
  • that is consistent with how Java is used.
  • works the same across all OS platforms.

Why so difference between Java and C though Java is derived from C

Why not? Why would this make any difference at all?

Let me give you a different example. The verb to "manufacture" literally meant man made, and yet today it almost means the opposite. Just because one language is derived from another doesn't mean they have to be the same.

Upvotes: 5

user3386109
user3386109

Reputation: 34839

Because historically, the printf function caused all sorts of headaches when the format specifiers were wrong, or arguments were missing. So languages derived from C, specifically C++ and Java, went to extraordinary lengths to avoid the printf problem.

At the same time, C compilers were improved to understand how printf works, and generate warnings when it's used incorrectly. Hence, the printf problem no longer exists for the most part (unless you ignore/disable the warnings).

Upvotes: 0

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