assign non-integer value to integer variable in C

Question

I am referring to GNU c tutorial it says assign non-integer value to integer variable will generate compile time error what exactly the error is,any example?? i tried

int a='A';

int a=2.323;

all are fine

what else could be to justify the statement??

Don't know what tutorial that is, but it's clearly wrong. But did it say warning instead of error? — simonzack, Nov 15 '14 at 14:41
`'A'` has type `int` in C. (http://stackoverflow.com/questions/433895/why-are-c-character-literals-ints-instead-of-chars) — Mat, Nov 15 '14 at 14:42
http://crasseux.com/books/ctutorial/Type-errors.html#Type%20errors — user4255847, Nov 15 '14 at 14:43
but the statement seems logical is there any example that helps me understand it — user4255847, Nov 15 '14 at 14:44
int a="A"; compiled without any error but with warning: initialization makes integer from pointer without a cast [enabled by default] and printf prints some random integer value to stdout — user4255847, Nov 15 '14 at 14:46

score 2 · Accepted Answer · edited May 23 '17 at 12:27

2

In some cases some conversions are being made. You can use -Wconversion in gcc for example to warn for implicit conversion.

(see Why assignment of double to int does not trigger gcc warnings?)

One example that does not compile is

struct account {
   int account_number;
   char *first_name;
   char *last_name;
   float balance;
};

struct account s;

int a=s;//breaks

The error message is in MSVC100 for example.

error C2440: 'initializing' : cannot convert from 'account' to 'int'

No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called

edited May 23 '17 at 12:27

Community

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answered Nov 15 '14 at 14:46

Gabriel

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yeah it gives error: incompatible types when initializing type ‘int’ using type ‘struct account’ – user4255847 Nov 15 '14 at 14:50
ok so choose it as the correct answer (some people downvoted it without knowing what they were doing) – Gabriel Nov 15 '14 at 14:50
but non-integer value could be other values too other than assigning the struct itself to a variable?? – user4255847 Nov 15 '14 at 14:52
some automatic conversions are made in this case for example an enum is an int so you can assign it to an int – Gabriel Nov 15 '14 at 14:55
what else could be other "non-integer " values if i were to assign it to a int variable to check for errors compiler generate – user4255847 Nov 15 '14 at 15:02
string for example would break – Gabriel Nov 15 '14 at 15:02
yeah but it gives warning as i mentioned not kind of error we can say specifically – user4255847 Nov 15 '14 at 15:04

assign non-integer value to integer variable in C

1 Answers1