Arithmetic conversions

[amjadtss]

Hello

I am new to C langauge

I have written a simple code to do addition of two numbers in C .
I was trying to check if gcc compiler catches type mismatch error.

Here is the code

#include <stdio.h>

char myadd ( char source , char dest)
{
int ret;
ret = source + dest;
return ret;
}

int main()
{
int j=5;
int k=4;
int m;
m=myadd(j,k);
printf("the sum is %d \n" , m);
return 0;
}

Compiling using gcc 4.1.1 on ubuntu 7.1 linux i get this output

gcc mystrcpy.c
./a.out

the sum is 9.

Does C does not distinguish between int and char type ??
is it gcc problem or in C char and int are interchangeable

thanks

[Savage]

Hello

I am new to C langauge

I have written a simple code to do addition of two numbers in C .
I was trying to check if gcc compiler catches type mismatch error.

Here is the code

#include <stdio.h>

char myadd ( char source , char dest)
{
int ret;
ret = source + dest;
return ret;
}

int main()
{
int j=5;
int k=4;
int m;
m=myadd(j,k);
printf("the sum is %d \n" , m);
return 0;
}

Compiling using gcc 4.1.1 on ubuntu 7.1 linux i get this output

gcc mystrcpy.c
./a.out

the sum is 9.

Does C does not distinguish between int and char type ??
is it gcc problem or in C char and int are interchangeable

thanks

It does distinguishes,but char is automatically casted to int..

This enables you to easily convert between char and int

Savage

[weaknessforcats]

The rule for aritmetic operators uses what are called Arithmetic Conversions.

Here's the rule:
If either operand is a long double, then the other is converted to a long double.
Next, if either operand is double, then the other is converted to double.
Next, if either operand is float, then the other is converted to float.
Next, integer promotions are performed on both operands:
If the value can be put in an int, then it is converted to an int
otherwise, it is converted to an unsigned int.
Now, if either operand is unsigned long, then the other is converted to unsigned long.
Now, if either operand is long, then the other is converted to long.
Now, if either operand is an unsigned int, then the other is converted to unsigned int.
Otherwise, both are ints.

Then the operator is performed and the type of the result is the type of the operands.


Keep these rules in mind when you mix types in calculations. Some unexplainable results will suddenly become explainable.

[amjadtss]

thank you for your prompt reply
I also want to ask if there is any good book to learn C and pointers in details

thanks

[r035198x]

Sorry guys, I had to rename this one.

[kreagan]

thank you for your prompt reply
I also want to ask if there is any good book to learn C and pointers in details

thanks

The best way to learn C is to practice. One well known book is:
The C (ansi C) Programming Language by Brian W. Kernighan.

If you want to learn more specific topic, such as pointers, I would suggest Google. Here is the first search I found with "C Pointers"

Pointers

It seems pretty detailed at a quick glance.

Another book I found was "The C Puzzle Book" by Alan Feuer. It's fun and interesting.