why does this program not compile for me?

kyle4579 · 07-13-2008, 09:12 AM

i wrote this program as an exercise involved in learning the c programming language:

Quote:

#include <stdio.h>

int conversion(int n);

main()
{

int celsius, fahr;

for (celsius = 0; celsius <= 300; celsius = celsius + 20)
printf("%3d %3d\n", celsius, conversion(celsius));

}

int conversion (int n)
{
int i;

for (i=0; i <= 300; ++i)
n = (9*n)/5 + 32;
return = n;
}

Unfortunately I get the following error message from the compiler:

Quote:

function.c: In function 'conversion':
function.c:22: error: expected expression before '=' token

why is this!?

any help is greatly appreciated, and please feel free to throw in any tips about programming or c, whether related or not! thanks

Mega Man X · 07-13-2008, 09:44 AM

Quote:

Originally Posted by kyle4579

i wrote this program as an exercise involved in learning the c programming language:

Code:

#include <stdio.h>

int conversion(int n);

main()
{

    int celsius, fahr;

    for (celsius = 0; celsius <= 300; celsius = celsius + 20)
        printf("%3d %3d\n", celsius, conversion(celsius));

}

int conversion (int n)
{
    int i;


    for (i=0; i <= 300; ++i)
    n = (9*n)/5 + 32;
    return = n;
}

Unfortunately I get the following error message from the compiler:

why is this!?

any help is greatly appreciated, and please feel free to throw in any tips about programming or c, whether related or not! thanks

Almost at the end of your program, you are assigning n to return:

Code:

return = n;

That is wrong. You will just want to return n, like this:

Code:

return n;

Regards!

kyle4579 · 07-17-2008, 04:11 AM

ah yes, that solves it! Thankyou very much

FranDango · 07-18-2008, 09:06 AM

My following notes are rather hints on C programming in general:

Quote:

for (i=0; i <= 300; ++i)

pre-incrementing 'i' is valid statement, but for human-readability it would be easier to use

Quote:

for (i=1; i <= 300; i++)

as it makes clearer that the first used value for i will be 1 and not 0.

I would rather write

Quote:

for (i=0; i <= 300; ++i) {
n = (9*n)/5 + 32;
}
return = n;

to make clear what happens inside the loop and what happens afterwards.

These remarks are not relevant for your quite simple code, but can be helpful for a larger codebase.

Linux Archive

jiml8 · 07-18-2008, 09:17 AM

You really need to take another look at conversion(). I don't think it is doing quite what you want it to do.

Why is there a for loop in it? You are computing the same value 300 times, then returning it.

ntubski · 07-18-2008, 09:58 AM

Quote:

Originally Posted by FranDango

Code:

for (i=0; i <= 300; ++i)

pre-incrementing 'i' is valid statement, but for human-readability it would be easier to use

Code:

for (i=1; i <= 300; i++)

as it makes clearer that the first used value for i will be 1 and not 0.

In the pre-incrementing loop the first value for i would be 0, so those are not equivalent. The ++i is C++'ism stemming from the fact that the pre increment operator usually more efficient on iterator objects (C++ Operator: Why should I use '++i' instead of 'i++'?). Although as jiml8 said, the loop shouldn't be there at all...