function problem

[JFK]

From the input file (mine is called ch10b) containing the following (the first digit representing the number sunny days
in a month, the second the number of rainy days):

4 9
3 12
6 12
8 8
12 5
The following output is to sent to the screen:

Weather Chart

Month 1
****
!!!!!!!!!

Month 2
***
!!!!!!!!!!!!

etc. through to month 5. Basically, the program converts the relevant int. to a char (* for sunny days, ! for rainy)
The spec for the program is to use a funtion called drawaline with 2 formal parameters of int length and char character.
I'm getting error message 'type mismatch in redirection of 'drawline[int,char]'. If anyone can shed light on this I'd be
very grateful!.

So far I have done:

#include<stdio.h>
#include<conio.h>

int length,
drawalinea,
drawalineb,
sunny_day,
rainy_day,
month;

char charactera = '*',
characterb = '!';

main()
{

FILE *ch10b = fopen("ch10b.dat", "r");
printf("Weather Chart \n\n");
month = 1;

char drawaline(int, char);

while(month <= 5)
{
fscanf(ch10b, "%d %d", &sunny_day, &rainy_day);
printf("Month %d", month);
drawalinea = drawaline(sunny_day, charactera);
drawalineb = drawaline(rainy_day, characterb);
printf("\n");
month ++;
}

fclose(ch10b);
getch();
}

drawaline(int length, char character)
{
int position = 1;
while (position <= length)
{
printf("%c", character);
position ++;
}
printf("\n");
}

[Garfield]

The 'type mistmatch' error message pretty much just says, "hey, you are trying to assign this type to this other type and it can't be done." Your problem is here:

>> drawalinea = drawaline(sunny_day, charactera);
>> drawalineb = drawaline(rainy_day, characterb);

What types are drawalinea and drawalineb? They are ints. What type does drawaline return? A char. That is illegal (hence, the error). What you are going to have to do is make the return compatable with the value being assigned the return value.

Understand?

--Garfield

[JFK]

Thanks for replying; I have changed the int to char for both the variables you mentioned, unfortunately I'm getting the same error message?

[Garfield]

Okay, I think I've got your problem. Right here:

>> drawaline(int length, char character)

This is the beginning (the declaration) of you function. You haven't written char or int (whichever you are using). The C compilier assumes that with nothing, you mean void. So, then it returns no value. Then you have this:

>> drawalinea = drawaline(sunny_day, charactera);
>> drawalineb = drawaline(rainy_day, characterb);

If the functions return no value, you are going to get an error to assign from a no value return. So, you would have to change this to:

drawaline(sunny_day, charactera);
drawaline(rainy_day, characterb);

I don't see the need to assign anything (whether it has a value or not) to those vars. They don't do anything. Then you should change your function prototype to:

void drawaline(int, char);

Tell me if this works. It should.

--Garfield

[JFK]

This is driving me nuts!! I'm still getting a redeclaration error..... here is my latest code (thanks for the help, it's really useful; I'm still new to C).

#include<stdio.h>
#include<conio.h>

int length,
sunny_day,
rainy_day,
month;

char charactera = '*',
characterb = '!';

void drawaline(int, char);

main()
{

FILE *ch10b = fopen("ch10b.dat", "r");
printf("Weather Chart \n\n");
month = 1;

while(month <= 5)
{
fscanf(ch10b, "%d %d", &sunny_day, &rainy_day);
printf("Month %d", month);
drawaline(sunny_day, charactera);
drawaline(rainy_day, characterb);
printf("\n");
month ++;
}

fclose(ch10b);
getch();
}

drawaline(int length, char character)
{
int position = 1;
while (position <= length)
{
printf("%c", character);
position ++;
}
printf("\n");
}

[Garfield]

Okay, I'm going to copy and paste this code and I'm going to go compile, see if it works, and fix it.

I'll be back in a little bit.

--Garfield

[Fordy]

You declared void on the declaration of "drawaline(int , char)"

put void on the front of the fuction when you use is


void drawaline(int length, char character)
{
int position = 1;
while (position <= length)
{
printf("%c", character);
position ++;
}
printf("\n");
}

[Garfield]

JFK, here is the working code. It compiled perfectly:

#include <stdio.h>

void drawline(int length, char character);

int main(int argc, char *argv[])
{
	FILE *fp;
	char *valid, line[20];
	int sun=0, rain=0, month=1;

	fp = fopen(argv[1], "r");
	if (fp == NULL)
	{
		printf("Put txt file in exe dir\n");
		return 0;
	}

	valid = fgets(line, sizeof(line), fp);

	while (valid != NULL)
	{
		sscanf(line, "%d %d", &sun, &rain);
		printf("Month %d:\n", month);
		drawline(sun, '*');
		drawline(rain, '!');
		month++;
		valid = fgets(line, sizeof(line), fp);
	}
	return 0;
}

void drawline(int length, char character)
{
	int i=0;

	while (i < length)
	{
		printf("%c", character);
		i++;
	}

	printf("\n");
}

Okay, a couple of changes I made. Instead of the program choosing the file, I just used *arcv[] and retreived the file from that. So, to run the program, you would do:

C:\Program Files:>Weather.exe <txt file here>

Understand?

--Garfield

[JFK]

Thanks for the response. I've looked at the code and I have pasted it into Borland 3 but I'm not sure how to run it.

Also, what is the '*argv[] ' syntax all about!? I haven't got as far as using that yet?

[Magos]

argv[] is an array containing the parameters when your program starts. argc is the number of parameters passed.

The first parameter (argv[0]) is the name of the program itself. If you run a program with this command (from a DOS prompt):

MyProg.exe 365 Hello

MyProg.exe is the first parameter (argv[0]), 365 is the second (argv[1]) and Hello is the third (argv[2]). This is very useful if you want to make your program more dynamic.

Another cool feature with this is that you can associate extensions (ie *.BMP, *.TXT, *.DOC or whatever) with your program. If you double-click on that file, the name and search path of that file will be passed as the second parameter to your program.
Now you just have to double-click on the file you want to open with your program instead of typing in the path to it every time you run it.