Hi there, i was tryig to make a program that calculates the horizontal distance of a projectilemotion usig the following four formulas:

angleRad)= angleDeg*(PI/180)
Vx=Vinitial*cos(angleRad)
Vy=Vinitial*sin(angleRad)
HorizontalDistance=Vx*2*(Vy/angleRad)

using four different user defied functions. please hav a look at my code and tell me where is the problem as i hav tried very hard to figure this out.

Thak You Very much

CODE:


This post has been edited by zizo: 12 Jan, 2008 - 05:28 AM

Have a look here for information on the syntax of writing and using functions.

http://www.cprogramming.com/tutorial/c/lesson4.html

(edit - corrected URL)

This post has been edited by Bench: 12 Jan, 2008 - 05:29 AM

wow that was a very quick reply, hehe....

but isnt my function declaration and prototype and function call and type all correct? i'm a begginner, so i dont understand the errors are sayin....something wrong with the function parameters.....please see if you can spot the error

thanx
zizo

Just a few things.

* You can't define functions inside of your main method.

* Your main method can't be void main(), it has to be int main(), and it must return either EXIT_SUCCESS or EXIT_FAILURE.

* You should almost always include <stdlib.h>.

* Functions and variables should always be lower case, upper case is typically reserved for preprocessor macros.

* You really should read up on functions an scope.

No, they're not - that's why I pasted the link. I strongly suggest you read it carefully and try the example program out for yourself in your IDE/compiler. Pay attention to the layout of the program, including the positioning of brackets/parenthesis, and where functions appear in the program relative to other parts of the program - then compare that closely with your program.


main can return any int value - though, the meaning of the return value is O/S dependent

You should include whichever header files you need, and omit those which you don't need. including a header for the sake of it doesn't really benefit anyone

This is a style issue. Whilst I personally would not advocate use of all-caps function names, there are no hard and fast rules on coding style, and advice offering "should always" guidelines on any coding style must be taken with a large pinch of salt. Such guidelines inevitably lead to disagreements and so-called "holy" wars between programmers with differing personal tastes. Consistency and overall readability are far bigger than whether a name is in upper/lower/mixed case IMHO.

This post has been edited by Bench: 12 Jan, 2008 - 04:26 PM

Bad choice of words then, but you should have main returning EXIT_SUCCESS or EXIT_FAILURE. I don't know of any platforms that actually do this, but from what I understand on some platforms return 0 would actually indicate an failure, hence the use of preprocessor macros (each system's preprocessor will be updated to ensure that EXIT_SUCCESS is replaced with the right value).

Kind of what you said I guess, just in more words.


Maybe I'm just doing something wrong, but I find that if I don't include stdlib.h but I'm using functions from the standard library (and I think it's safe to say that most programs do) I get warnings when trying to compile (despite the fact that the functions work fine).



Including stdlib.h ensures that those warnings don't show up.

man i did read the link that u gave me and i replaced all my function names to lower case, and added stdlib.h but it did not even erduce a warning......hehehehe

i still get these errors and warnings:
--------------------Configuration: Text1 - Win32 Debug--------------------
Compiling...
Text1.c
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(29) : error C2115: '=' : incompatible types
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(29) : error C2106: '=' : left operand must be l-value
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(29) : warning C4550: expression evaluates to a function which is missing an argument list
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(30) : warning C4550: expression evaluates to a function which is missing an argument list
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(30) : warning C4098: 'main' : 'void' function returning a value
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(34) : error C2115: 'function' : incompatible types
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(34) : warning C4024: 'cos' : different types for formal and actual parameter 1
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(34) : error C2115: '=' : incompatible types
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(34) : error C2106: '=' : left operand must be l-value
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(34) : warning C4550: expression evaluates to a function which is missing an argument list
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(35) : warning C4550: expression evaluates to a function which is missing an argument list
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(35) : warning C4098: 'main' : 'void' function returning a value
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(39) : error C2115: 'function' : incompatible types
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(39) : warning C4024: 'sin' : different types for formal and actual parameter 1
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(39) : error C2115: '=' : incompatible types
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(39) : error C2106: '=' : left operand must be l-value
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(39) : warning C4550: expression evaluates to a function which is missing an argument list
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(40) : warning C4550: expression evaluates to a function which is missing an argument list
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(40) : warning C4098: 'main' : 'void' function returning a value
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(44) : error C2296: '*' : illegal, left operand has type 'double (__cdecl *)(double )'
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(44) : error C2296: '/' : illegal, left operand has type 'double (__cdecl *)(double )'
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(44) : error C2297: '/' : illegal, right operand has type 'double (__cdecl *)(double )'
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(45) : warning C4550: expression evaluates to a function which is missing an argument list
C:\Documents and Settings\SuAdDaRrH\Desktop\New Folder\Text1.c(45) : warning C4098: 'main' : 'void' function returning a value
Error executing cl.exe.

Text1.exe - 11 error(s), 13 warning(s)

None of those things are related to your error - did you actually look closely at the example program/s in the link? Specifically, the positioning of functions and brackets?

Look at this

Compare and contrast with your program
Look at three things -
- Where the function name appears in relation to its brackets which enclose the body of that function
- Where you've attempted to assign a value to the function name (You can't do this).
- Where the function appears in your program in relation to the ending brace of main.