assigning float into int variable causes no warning

So, given the following code:

int main(void) {
int i;
i = 12.1234;
i++;
return 0;
}

I compiled the code and I expected and wanted the compiler to give me a warning, but it didn't. Is my compiler configured wrong? Is there a way to make my compiler give warning?

This is what I used

>cc -Wall test.c

Since you confirmed your compiler is `gcc` then you can use the [-Wconversion](

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) flag which should provide a warning similar to this:

warning: conversion to 'int' alters 'double' constant value [-Wfloat-conversion]
i = 12.1234;
^

Converting a floating point value to *int* is perfectly valid it will discard the fractional part and as long as the value can be represented, otherwise you have undefined behavior. The C99 draft standard covers this in section `4.9` *Floating-integral conversions*:

> A prvalue of a floating point type can be converted to a prvalue of an
> integer type. The conversion truncates; that is, the fractional part
> is discarded. The behavior is undefined if the truncated value cannot
> be represented in the destination type.

A float value **can be assigned** to an integer variable but an **implicit conversion** occurs when **compiler** forces a float value to be assigned as an integer.

The digits after the decimal notation in the float value get lost after assigning a float to an integer.

Edit: casting -> conversion

Thanks R..

You may expect that `-Wall` does enable *ALL* warnings, but it doesn't!
There are a lot of warnings that doesn't even make sense in the wrong environment.

It is an aggregation of the following flags:

> -Waddress
> -Warray-bounds (only with -O2)
> -Wc++11-compat
> -Wchar-subscripts
> -Wenum-compare (in C/ObjC; this is on by default in C++)
> -Wimplicit-int (C and Objective-C only)
> -Wimplicit-function-declaration (C and Objective-C only)
> -Wcomment
> -Wformat
> -Wmain (only for C/ObjC and unless -ffreestanding)
> -Wmaybe-uninitialized
> -Wmissing-braces (only for C/ObjC)
> -Wnonnull
> -Wparentheses
> -Wpointer-sign
> -Wreorder
> -Wreturn-type
> -Wsequence-point
> -Wsign-compare (only in C++)
> -Wstrict-aliasing
> -Wstrict-overflow=1
> -Wswitch
> -Wtrigraphs
> -Wuninitialized
> -Wunknown-pragmas
> -Wunused-function
> -Wunused-label
> -Wunused-value
> -Wunused-variable
> -Wvolatile-register-var
as described here:

[To see links please register here]

What you need is `-Wconversion` as mentioned above. Another quite useful flag may be `-Wextra`.