Misplaced else in function main -- help?

rollyah · 04-25-2010, 12:44 AM

Hello,

i'm a newbie with C
i started learning it like 2 weeks ago by getting a few ebooks that i've found online..

attached with the ebook a booklet full of exercises to test what i've learned for each chapter but without the solutions .. :S

i managed to get through most tests but im stuck at these two.. hope you could point out wht im doing wrong:

Quote:

Write a complete C program that asks the user to enter continuously a series of words and the
word “end” to stop.
For each word entered, you should output the number of characters of this word and then ask him
to enter the other word.
Finally, when he finished entering all the words, you should output the number of words entered
(excluding “end”)

Code:

#include <stdio.h>
int main(void)
{
char word[256];
char stop[3]="end";
int cnt=0;
printf("Enter a word to know it's number of characters. once finished enter \"end\" to stop\n");
scanf("%s",&word);
while (stop!=word)
printf("The number of characters of %s is %u\n",word,strlen(word));
cnt = cnt++;
else
printf("you've decided to stop. you entered %d words so far.\n",cnt);
return 0;	
}

and this is the error:

Borland C++ 5.5.1 for Win32 Copyright (c) 1993, 2000 Borland
tma.c:
Warning W8065 tma.c 10: Call to function 'strlen' with no prototype in function main
Error E2054 tma.c 11: Misplaced else in function main
*** 1 errors in Compile ***

Quote:

Write a complete C program that calculates the roots of any quadratic equation of the form ax2 +
bx + c = 0 where a, b and c are variables that should be entered by user.
First, if a = 0 then the root is x= -c/b
otherwise, you have to find Δ, Δ=b2 – 4ac
If Δ< 0 there are no roots
If Δ= 0 we have 2 double roots: x1 = x2 = -b/2a
If Δ>0, two roots x1 = (-b-√Δ)/2a and (–b +√Δ)/2a
Hint: you can include math library to use some math functions

Code:

#include "stdio.h"
#include "math.h"

void main()
{
int a,b,c,delta;
float x,x1;
printf("\n Enter values of a,b,c for finding roots of a quadratic eq:\n");
scanf("%d%d%d",&a,&b,&c);

if (a == 0) {
x = -c/b
printf("in this case the root is %f",x);
}
else
 delta=b^2-4*a*c

if ( delta<0)
{
printf("there are no roots")
}
if (delta == 0)
{
x= -b/(2*a);
printf("we have double roots %f",x);
}
if (delta>0)
{ 
x = (-b-sqrt(delta))/2*a)
x1 = (-b+sqrt(delta)/2*a
printf("we have two roots which are %f and %f",x,x1);
}
}

ERROR:

Quote:

Borland C++ 5.5.1 for Win32 Copyright (c) 1993, 2000 Borland
new.c:
Error E2379 new.c 13: Statement missing ; in function main
Error E2379 new.c 18: Statement missing ; in function main
Warning W8004 new.c 33: 'x' is assigned a value that is never used in function main
Warning W8004 new.c 33: 'delta' is assigned a value that is never used in function main
*** 2 errors in Compile ***

**laserlight** · 04-25-2010, 01:00 AM

The else must have a matching if, but there isn't any. In fact, it looks like you don't need an else.

By the way, you should indent your code properly. If you do so, you may discover a logic error due to the lack of braces.

rollyah · 04-25-2010, 01:07 AM

Quote:

Originally Posted by laserlight

The else must have a matching if, but there isn't any. In fact, it looks like you don't need an else.

By the way, you should indent your code properly. If you do so, you may discover a logic error due to the lack of braces.

thanks for your reply

but if i remove else wouldn't that lead to an infinite loop?

im struggling to learn the how Tos for C so thanks again for helping out

Elysia · 04-25-2010, 01:18 AM

Start by doing so... First, indent your code.
Second, check all your lines of code for missing ; (there are at least two).
Third, check all your lines for missing parenthesises (there is at least one).
And fourth, there is a problem in the algorithm. a^2 is not a squared (it's a XOR 2). Nor should there be any squared variables in the formula. Look at it again, closely.
And last, you are missing parenthesises again. When you have a*b/c*d, you'll have to add parenthesises, remember? This is like a calculator.
And change void main to int main.

nonpuz · 04-25-2010, 03:17 AM

Also your stop[3] doesn't leave room for a trailing null so it is actually an array of characters, not a valid C string.

You should use char stop[] = "end"; this will include the trailing \0. This is important due to the next error (besides the ones mentioned above) that you are trying to compare a character array to a string using a simple ==.

If you make end[] a string as I said above, then you can use strcmp(end,word) == 0 to see if they match.

Of course you also need to include string.h for strcmp and strlen() which you are already using.

rollyah · 04-30-2010, 12:04 PM

so i found my prob with the first excercise..
though i'm still facing issues with the 2nd..

Code:

#include <stdio.h>
#include <math.h>
int main (void)
{
int a,b,c;
float x,x1,x2,y,delta;
     printf("enter three numbers please\n");
	 scanf("%d%d%d",a,b,c);
	 delta=b*b-4*a*c;
	     if (a==0)
		     x=(-c/b);
			 printf("the root is %f\n",x);
		 else 
		     printf("Delta=b2-4ac is equal to %f\n",delta);
			 
		    if (delta<0)
			     printf("there are no roots\n");
			else
			    if (delta==0)
			        y=(-b/(2*a));
		            printf("we have double roots x1=x2=%d/2*%d=%f\n",a,b,y);
				else
			        if (delta>0)
			            x1=((-b+sqrt(delta))/(2*a));
				        x2=((-b+sqrt(delta))/(2*a));
				        printf("there are two roots which are %f and %f\n",x1,x2);
				 
return 0;	     	 
}

error:

Quote:

Error E2054 roland2.c 13: Misplaced else in function main
Error E2054 roland2.c 22: Misplaced else in function main
*** 2 errors in Compile ***

Elysia · 04-30-2010, 12:07 PM

Fix your indentation.
It's your tool for finding these kinds of things.

rollyah · 04-30-2010, 12:11 PM

Quote:

Originally Posted by Elysia

Fix your indentation.
It's your tool for finding these kinds of things.

thank you for your advice.. but im struggling here..
i tried fxing my indentation over and over again..
i'm not sure i'm even doing it right..
any advice?

Elysia · 04-30-2010, 12:13 PM

For example, Visual Studio has an indentation tool. There are others.
But it isn't difficult to do it yourself. Consider this indented code of yours. You should be able to spot the problem:

Code:

#include <stdio.h>
#include <math.h>
int main (void)
{
	int a,b,c;
	float x,x1,x2,y,delta;
	printf("enter three numbers please\n");
	scanf("%d%d%d",a,b,c);
	delta=b*b-4*a*c;
	if (a==0)
		x=(-c/b);
	printf("the root is %f\n",x);
	else 
		printf("Delta=b2-4ac is equal to %f\n",delta);

	if (delta<0)
		printf("there are no roots\n");
	else
		if (delta==0)
			y=(-b/(2*a));
	printf("we have double roots x1=x2=%d/2*%d=%f\n",a,b,y);
		else
			if (delta>0)
				x1=((-b+sqrt(delta))/(2*a));
	x2=((-b+sqrt(delta))/(2*a));
	printf("there are two roots which are %f and %f\n",x1,x2);

	return 0;	     	 
}

rollyah · 04-30-2010, 12:17 PM

Quote:

Originally Posted by Elysia

For example, Visual Studio has an indentation tool. There are others.
But it isn't difficult to do it yourself. Consider this indented code of yours. You should be able to spot the problem:

Code:

#include <stdio.h>
#include <math.h>
int main (void)
{
	int a,b,c;
	float x,x1,x2,y,delta;
	printf("enter three numbers please\n");
	scanf("%d%d%d",a,b,c);
	delta=b*b-4*a*c;
	if (a==0)
		x=(-c/b);
	printf("the root is %f\n",x);
	else 
		printf("Delta=b2-4ac is equal to %f\n",delta);

	if (delta<0)
		printf("there are no roots\n");
	else
		if (delta==0)
			y=(-b/(2*a));
	printf("we have double roots x1=x2=%d/2*%d=%f\n",a,b,y);
		else
			if (delta>0)
				x1=((-b+sqrt(delta))/(2*a));
	x2=((-b+sqrt(delta))/(2*a));
	printf("there are two roots which are %f and %f\n",x1,x2);

	return 0;	     	 
}

im using notepad
and command line Borland C++ 5.5.1 for Win32 Copyright (c) 1993, 2000 Borland

i downloaded "Microsoft Visual C++ 2008 Express Edition"
though i'm ashamed to admit that i didn't know how to use it..

PS: thanks for your effort by indenting but i'm still not noticing the prob..
i'm reading the notes ive taken from the net over and over again..
im pretty sure there's something im missing but im not finding it out..

Elysia · 04-30-2010, 12:24 PM

Code:

#include <stdio.h>
#include <math.h>
int main (void)
{
	int a,b,c;
	float x,x1,x2,y,delta;
	printf("enter three numbers please\n");
	scanf("%d%d%d",a,b,c);
	delta=b*b-4*a*c;
	if (a==0)
		x=(-c/b);
	printf("the root is %f\n",x);
	else 
		printf("Delta=b2-4ac is equal to %f\n",delta);

	if (delta<0)
		printf("there are no roots\n");
	else
		if (delta==0)
			y=(-b/(2*a));
	printf("we have double roots x1=x2=%d/2*%d=%f\n",a,b,y);
		else
			if (delta>0)
				x1=((-b+sqrt(delta))/(2*a));
	x2=((-b+sqrt(delta))/(2*a));
	printf("there are two roots which are %f and %f\n",x1,x2);

	return 0;	     	 
}

Problematic lines are in red.
We see from the indentation that, for example, the printf lines do not belong to the IF statement. Braces are required if you want more than one statement in an if.
As a result of this, the else does not directly follow the if, and therefore, the compiler cannot determine which if statement it belongs to and so it complains.
There are many good tutorials on Visual Studio on the web.
Even if you don't use it, you shouldn't use Notepad for creating code. Either use a real editor or an IDE.

rollyah · 04-30-2010, 12:37 PM

Quote:

Originally Posted by Elysia

Code:

#include <stdio.h>
#include <math.h>
int main (void)
{
	int a,b,c;
	float x,x1,x2,y,delta;
	printf("enter three numbers please\n");
	scanf("%d%d%d",a,b,c);
	delta=b*b-4*a*c;
	if (a==0)
		x=(-c/b);
	printf("the root is %f\n",x);
	else 
		printf("Delta=b2-4ac is equal to %f\n",delta);

	if (delta<0)
		printf("there are no roots\n");
	else
		if (delta==0)
			y=(-b/(2*a));
	printf("we have double roots x1=x2=%d/2*%d=%f\n",a,b,y);
		else
			if (delta>0)
				x1=((-b+sqrt(delta))/(2*a));
	x2=((-b+sqrt(delta))/(2*a));
	printf("there are two roots which are %f and %f\n",x1,x2);

	return 0;	     	 
}

Problematic lines are in red.
We see from the indentation that, for example, the printf lines do not belong to the IF statement. Braces are required if you want more than one statement in an if.
As a result of this, the else does not directly follow the if, and therefore, the compiler cannot determine which if statement it belongs to and so it complains.
There are many good tutorials on Visual Studio on the web.
Even if you don't use it, you shouldn't use Notepad for creating code. Either use a real editor or an IDE.

ah that thts the prob..
i checked all my notes i didnt have anything concerning "braces are required if theres more than a statement"
thanks for the info..
i'm gonna look into mroe tutorials online..
PS: i were able to compile it but it's crashing..
any logical error that you can notice?
don't point it out i want to try and find it out on my own if possible..
sorry for being pushy..

Elysia · 04-30-2010, 12:45 PM

All I can say is that it's not a logic problem that causes your crash.
I could elaborate on where and why, if you want, but seeing as you did state you want to find it yourself, you'll have to make another reply if you want it.
Take your time.

rollyah · 04-30-2010, 12:51 PM

Quote:

Originally Posted by Elysia

All I can say is that it's not a logic problem that causes your crash.
I could elaborate on where and why, if you want, but seeing as you did state you want to find it yourself, you'll have to make another reply if you want it.
Take your time.

i commented everything to be able to pinpoint the prob..

Code:

#include <stdio.h>
//#include <math.h>
int main (void)
{
	int a,b,c;
	//float x,x1,x2,y,delta;
	printf("enter your first number	please\n");
	scanf("%d",a);
	printf("enter your second number please\n");
	scanf("%d",b);
	printf("enter your third number	please\n");
    scanf("%d",c);
	printf("%d,%d,%d",a,b,c);
	//delta=(b*(b-(4*a*c)));
	//if (a==0)
	    //{
		//x=(-c/b);
	    //printf("the root is %f\n",x);
		//}
	
	//else 
		//printf("Delta=b2-4ac is equal to %f\n",delta);

	//if (delta<0)
	//	printf("there are no roots\n");
	//else
	//if (delta==0)
	//{
	//		y=(-b/(2*a));
	 //       printf("we have double roots x1=x2=%d/2*%d=%f\n",a,b,y);
//			}
//	else
//	if (delta>0)
//			x1=((-b+sqrt(delta))/(2*a));
//	        x2=((-b+sqrt(delta))/(2*a));
//	printf("there are two roots which are %f and %f\n",x1,x2);

	return 0;	     	 
}

and it's still crashing..
what did i do wrong?

Elysia · 04-30-2010, 12:53 PM

scanf requires pointers to where it should store the input. You are merely passing the contents of the variables to scanf.
Aside from that, you should probably be getting warnings in some form or another.

04-25-2010, 01:00 AM	#2
laserlight C++ Witch Join Date: Oct 2003 Location: Singapore Posts: 12,704	The else must have a matching if, but there isn't any. In fact, it looks like you don't need an else. By the way, you should indent your code properly. If you do so, you may discover a logic error due to the lack of braces. __________________ C + C++ Compiler: MinGW port of GCC Build + Version Control System: SCons + Bazaar Look up a C/C++ Reference and learn How To Ask Questions The Smart Way
laserlight is online now

04-25-2010, 01:18 AM	#4
Elysia The Beautiful C++ Utopia Join Date: Oct 2007 Posts: 16,455	Start by doing so... First, indent your code. Second, check all your lines of code for missing ; (there are at least two). Third, check all your lines for missing parenthesises (there is at least one). And fourth, there is a problem in the algorithm. a^2 is not a squared (it's a XOR 2). Nor should there be any squared variables in the formula. Look at it again, closely. And last, you are missing parenthesises again. When you have ab/cd, you'll have to add parenthesises, remember? This is like a calculator. And change void main to int main. __________________ WARNING: Any and all code samples I post are not tested unless explicitly mentioned otherwise. Use at your own risk. Using: Microsoft Windows™ 7 Professional (x64), Microsoft Visual Studio™ 2010 Ultimate, C++0x "Thanks Elysia. You're a programming master! How the hell do you know every thing?" "Thanks for all your help. It's obvious yall really know what you're talking about when it comes to OOP/C++ stuff." Quoted... at least once. Why did the Java creators shoot themselves in the foot?
Elysia is offline

04-25-2010, 03:17 AM	#5
nonpuz Ultraviolence Connoisseur Join Date: Mar 2004 Posts: 239	Also your stop[3] doesn't leave room for a trailing null so it is actually an array of characters, not a valid C string. You should use char stop[] = "end"; this will include the trailing \0. This is important due to the next error (besides the ones mentioned above) that you are trying to compare a character array to a string using a simple ==. If you make end[] a string as I said above, then you can use strcmp(end,word) == 0 to see if they match. Of course you also need to include string.h for strcmp and strlen() which you are already using.
nonpuz is offline

04-30-2010, 12:07 PM	#7
Elysia The Beautiful C++ Utopia Join Date: Oct 2007 Posts: 16,455	Fix your indentation. It's your tool for finding these kinds of things. __________________ WARNING: Any and all code samples I post are not tested unless explicitly mentioned otherwise. Use at your own risk. Using: Microsoft Windows™ 7 Professional (x64), Microsoft Visual Studio™ 2010 Ultimate, C++0x "Thanks Elysia. You're a programming master! How the hell do you know every thing?" "Thanks for all your help. It's obvious yall really know what you're talking about when it comes to OOP/C++ stuff." Quoted... at least once. Why did the Java creators shoot themselves in the foot?
Elysia is offline

04-30-2010, 12:13 PM	#9
Elysia The Beautiful C++ Utopia Join Date: Oct 2007 Posts: 16,455	For example, Visual Studio has an indentation tool. There are others. But it isn't difficult to do it yourself. Consider this indented code of yours. You should be able to spot the problem: Code: #include <stdio.h> #include <math.h> int main (void) { int a,b,c; float x,x1,x2,y,delta; printf("enter three numbers please\n"); scanf("%d%d%d",a,b,c); delta=bb-4ac; if (a==0) x=(-c/b); printf("the root is %f\n",x); else printf("Delta=b2-4ac is equal to %f\n",delta); if (delta<0) printf("there are no roots\n"); else if (delta==0) y=(-b/(2a)); printf("we have double roots x1=x2=%d/2%d=%f\n",a,b,y); else if (delta>0) x1=((-b+sqrt(delta))/(2a)); x2=((-b+sqrt(delta))/(2a)); printf("there are two roots which are %f and %f\n",x1,x2); return 0; } __________________ WARNING:* Any and all code samples I post are not tested unless explicitly mentioned otherwise. Use at your own risk. Using: Microsoft Windows™ 7 Professional (x64), Microsoft Visual Studio™ 2010 Ultimate, C++0x "Thanks Elysia. You're a programming master! How the hell do you know every thing?" "Thanks for all your help. It's obvious yall really know what you're talking about when it comes to OOP/C++ stuff." Quoted... at least once. Why did the Java creators shoot themselves in the foot?
Elysia is offline

04-30-2010, 12:24 PM	#11
Elysia The Beautiful C++ Utopia Join Date: Oct 2007 Posts: 16,455	Code: #include <stdio.h> #include <math.h> int main (void) { int a,b,c; float x,x1,x2,y,delta; printf("enter three numbers please\n"); scanf("%d%d%d",a,b,c); delta=bb-4ac; if (a==0) x=(-c/b); printf("the root is %f\n",x); else printf("Delta=b2-4ac is equal to %f\n",delta); if (delta<0) printf("there are no roots\n"); else if (delta==0) y=(-b/(2a)); printf("we have double roots x1=x2=%d/2%d=%f\n",a,b,y); else if (delta>0) x1=((-b+sqrt(delta))/(2a)); x2=((-b+sqrt(delta))/(2a)); printf("there are two roots which are %f and %f\n",x1,x2); return 0; } Problematic lines are in red. We see from the indentation that, for example, the printf lines do not belong to the IF statement. Braces are required if you want more than one statement in an if. As a result of this, the else does not directly follow the if, and therefore, the compiler cannot determine which if statement it belongs to and so it complains. There are many good tutorials on Visual Studio on the web. Even if you don't use it, you shouldn't use Notepad for creating code. Either use a real editor or an IDE. __________________ WARNING:* Any and all code samples I post are not tested unless explicitly mentioned otherwise. Use at your own risk. Using: Microsoft Windows™ 7 Professional (x64), Microsoft Visual Studio™ 2010 Ultimate, C++0x "Thanks Elysia. You're a programming master! How the hell do you know every thing?" "Thanks for all your help. It's obvious yall really know what you're talking about when it comes to OOP/C++ stuff." Quoted... at least once. Why did the Java creators shoot themselves in the foot?
Elysia is offline

04-30-2010, 12:45 PM	#13
Elysia The Beautiful C++ Utopia Join Date: Oct 2007 Posts: 16,455	All I can say is that it's not a logic problem that causes your crash. I could elaborate on where and why, if you want, but seeing as you did state you want to find it yourself, you'll have to make another reply if you want it. Take your time. __________________ WARNING: Any and all code samples I post are not tested unless explicitly mentioned otherwise. Use at your own risk. Using: Microsoft Windows™ 7 Professional (x64), Microsoft Visual Studio™ 2010 Ultimate, C++0x "Thanks Elysia. You're a programming master! How the hell do you know every thing?" "Thanks for all your help. It's obvious yall really know what you're talking about when it comes to OOP/C++ stuff." Quoted... at least once. Why did the Java creators shoot themselves in the foot?
Elysia is offline

04-30-2010, 12:53 PM	#15
Elysia The Beautiful C++ Utopia Join Date: Oct 2007 Posts: 16,455	scanf requires pointers to where it should store the input. You are merely passing the contents of the variables to scanf. Aside from that, you should probably be getting warnings in some form or another. __________________ WARNING: Any and all code samples I post are not tested unless explicitly mentioned otherwise. Use at your own risk. Using: Microsoft Windows™ 7 Professional (x64), Microsoft Visual Studio™ 2010 Ultimate, C++0x "Thanks Elysia. You're a programming master! How the hell do you know every thing?" "Thanks for all your help. It's obvious yall really know what you're talking about when it comes to OOP/C++ stuff." Quoted... at least once. Why did the Java creators shoot themselves in the foot?
Elysia is offline

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