Programming Forums > Application Development > C

Blighttdm · Nov 17th, 2005, 10:10 PM

The Problem:
As I try to compile a small C program I get the following error messages:

ghp11.c:25: error: syntax error before '{' token
ghp11.c: At top level:
ghp11.c:30: error: syntax error before '(' token
ghp11.c:30: error: `len' undeclared here (not in a function)
ghp11.c:30: error: syntax error before '==' token
ghp11.c:33: warning: data definition has no type or storage class
ghp11.c:34: error: syntax error before '}' token
ghp11.c:33: error: storage size of `input' isn't known

These errors occur in the second

Code:

(Toggle Plain Text)

 if(input[len]=='y')
 {
  input[len]='i';
  input[len+1]='e';
  input[len+2]='s';
 }

elseif(input[len]=='s')
 {
  input[len+1]='e';
  input[len+2]='s';
 }

elseif(((input[len-1]=='c')&&(input[len]=='h'))) //line 30
 {
  input[len+1]='e';
  input[len+2]='s';
 }                                               //line 34

elseif((input[len-1]=='s')&&(input[len]=='h'))
 {
  input[len+1]='e';
  input[len+2]='s';
 }

Now I know a couple of reasons it may not work but I'm not sure and my manual gives me little advice. Could it be:
-Len can't be altered like that because it was a result of strlen?
-I din't initialize a variable properly?
-Some string syntax?
-General syntax that I missed?
-I missed some big idea and messed up big time?

As always thank you for your help,
Blight

Mjordan2nd · Nov 17th, 2005, 10:19 PM

Shouldn't else and if be seperated? Also, could you show us your decleration for input? Actually, it would be easier if you just put your whole code up so we can compile and fix the errors ourselves.

1.) Len should be able to be altered, though I don't see you altering len anywhere.

2.) This may be possible for input, perhaps.

3.) Other than the else if part, I don't see any syntactical errors right off the bat.

4.) Again, else-if

5.) No, you seem to have the idea down, so I don't think this is it.

Blighttdm · Nov 17th, 2005, 10:31 PM

Well here it is, I was just following the guidelines and not posting the whole thing. Hope it helps.

(Toggle Plain Text)

/*********************************
*********************************/

#include <stdio.h>
#include <string.h>

int main (void)
{
 char input[30];
 int len;

 printf("Please enter a noun(up to 28 characters) to pluarize:");
 scanf("%s",input);
 
 len=strlen(input);

 if(input[len]=='y')
 {
  input[len]='i';
  input[len+1]='e';
  input[len+2]='s';
 }

elseif(input[len]=='s')
 {
  input[len+1]='e';
  input[len+2]='s';
 }

elseif(((input[len-1]=='c')&&(input[len]=='h')))
 {
  input[len+1]='e';
  input[len+2]='s';
 }

elseif((input[len-1]=='s')&&(input[len]=='h'))
 {
  input[len+1]='e';
  input[len+2]='s';
 }


else
{
input[len+1]='s';
}

printf("\n%s is the plural.",input);

return(0);
}

Infinite Recursion · Nov 17th, 2005, 10:41 PM

Change "elseif" to "else if" ... it will compile then.
The code needs some work as the plural for "gun" is not "gun" as your program suggests.

Blighttdm · Nov 18th, 2005, 5:51 AM

So, why is it not appending any words I enter?

Polyphemus_ · Nov 18th, 2005, 6:10 AM

This code isn't gonna work, since you don't terminate the string with a 0 character ('\0').

DaWei · Nov 18th, 2005, 6:16 AM

You are not using scanf in such a way as to prevent overrunning the buffer, which can lead to improper operation and crashing of your program. Your buffer, with a length of 30, can hold a 29-character string, maximum, since your string will require a terminating null if you intend to pass it to a C-string function such as printf or strlen. When you overwrite the terminating null that IS there with your plural ending, you're bound to get odd results, if not a memory violation, because you're not terminating your addition.

Blighttdm · Nov 18th, 2005, 4:53 PM

So how whould I go about fixing this because I'm lost.

jim mcnamara · Nov 18th, 2005, 5:14 PM

Here - I fixed the first block - you can duplicate it down into the other if blocks.

(Toggle Plain Text)

#include <stdio.h>
#include <string.h>

int main (void)
{
 char input[30]={0x0}; /* initialize the string */
 int len=0;

 printf("Please enter a noun(up to 28 characters) to pluarize:");
 fgets(input,sizeof(input),stdin);  /* prevent user enter LARGE word to crash
                                           this program */
 
 len=strlen(input);  /* add an if statment to be sure your word is okay length */
 len--;                 /* characters start counting from zero, not one 
                             so the last character of the string is len-1 -- 
                              len-- decrements len */
 if(input[len]=='y')
 {
  input[len]='i';
  input[len+1]='e';
  input[len+2]='s';
 }
  /* it works just fine up to here */

Blighttdm · Nov 18th, 2005, 5:22 PM

Firstly thanks,
Second, I just want to understand how these corrections work.

(Toggle Plain Text)

fgets(input,sizeof(input),stdin);

I know gets is used for strings but why use it in a single string?
Also stdin, I have no idea what that does, does it involve strings or some type of typical error as a result of gets?

(Toggle Plain Text)

len--;

Why do I have to decrement len? Is it for appending reasons?

Nov 17th, 2005, 10:10 PM	#1
Blighttdm Newbie Join Date: Oct 2005 Posts: 17 Rep Power: 0	String error in if statement The Problem: As I try to compile a small C program I get the following error messages: (Toggle Plain Text) ghp11.c:25: error: syntax error before '{' token ghp11.c: At top level: ghp11.c:30: error: syntax error before '(' token ghp11.c:30: error: `len' undeclared here (not in a function) ghp11.c:30: error: syntax error before '==' token ghp11.c:33: warning: data definition has no type or storage class ghp11.c:34: error: syntax error before '}' token ghp11.c:33: error: storage size of `input' isn't known ghp11.c:25: error: syntax error before '{' token ghp11.c: At top level: ghp11.c:30: error: syntax error before '(' token ghp11.c:30: error: `len' undeclared here (not in a function) ghp11.c:30: error: syntax error before '==' token ghp11.c:33: warning: data definition has no type or storage class ghp11.c:34: error: syntax error before '}' token ghp11.c:33: error: storage size of `input' isn't known These errors occur in the second Code: (Toggle Plain Text) if(input[len]=='y') { input[len]='i'; input[len+1]='e'; input[len+2]='s'; } elseif(input[len]=='s') { input[len+1]='e'; input[len+2]='s'; } elseif(((input[len-1]=='c')&&(input[len]=='h'))) //line 30 { input[len+1]='e'; input[len+2]='s'; } //line 34 elseif((input[len-1]=='s')&&(input[len]=='h')) { input[len+1]='e'; input[len+2]='s'; } if(input[len]=='y') { input[len]='i'; input[len+1]='e'; input[len+2]='s'; } elseif(input[len]=='s') { input[len+1]='e'; input[len+2]='s'; } elseif(((input[len-1]=='c')&&(input[len]=='h'))) //line 30 { input[len+1]='e'; input[len+2]='s'; } //line 34 elseif((input[len-1]=='s')&&(input[len]=='h')) { input[len+1]='e'; input[len+2]='s'; } Now I know a couple of reasons it may not work but I'm not sure and my manual gives me little advice. Could it be: -Len can't be altered like that because it was a result of strlen? -I din't initialize a variable properly? -Some string syntax? -General syntax that I missed? -I missed some big idea and messed up big time? As always thank you for your help, Blight

Nov 17th, 2005, 10:19 PM	#2
Mjordan2nd The Supreme Ruler Join Date: May 2004 Location: Houston Posts: 1,476 Rep Power: 6	Shouldn't else and if be seperated? Also, could you show us your decleration for input? Actually, it would be easier if you just put your whole code up so we can compile and fix the errors ourselves. 1.) Len should be able to be altered, though I don't see you altering len anywhere. 2.) This may be possible for input, perhaps. 3.) Other than the else if part, I don't see any syntactical errors right off the bat. 4.) Again, else-if 5.) No, you seem to have the idea down, so I don't think this is it. __________________ "Every gun that is made, every warship launched, every rocket signifies, in the final sense, a theft from those who hunger and are not fed, from those who are cold and are not clothed. The world in arms is not spending money alone. It is spending the sweat of its laborers, the genius of its scientists, the hopes of its children." - Dwight D. Eisenhower

Nov 17th, 2005, 10:31 PM	#3
Blighttdm Newbie Join Date: Oct 2005 Posts: 17 Rep Power: 0	Well here it is, I was just following the guidelines and not posting the whole thing. Hope it helps. (Toggle Plain Text) /******************************* *****************************/ #include <stdio.h> #include <string.h> int main (void) { char input[30]; int len; printf("Please enter a noun(up to 28 characters) to pluarize:"); scanf("%s",input); len=strlen(input); if(input[len]=='y') { input[len]='i'; input[len+1]='e'; input[len+2]='s'; } elseif(input[len]=='s') { input[len+1]='e'; input[len+2]='s'; } elseif(((input[len-1]=='c')&&(input[len]=='h'))) { input[len+1]='e'; input[len+2]='s'; } elseif((input[len-1]=='s')&&(input[len]=='h')) { input[len+1]='e'; input[len+2]='s'; } else { input[len+1]='s'; } printf("\n%s is the plural.",input); return(0); } /***************************** *******************************/ #include <stdio.h> #include <string.h> int main (void) { char input[30]; int len; printf("Please enter a noun(up to 28 characters) to pluarize:"); scanf("%s",input); len=strlen(input); if(input[len]=='y') { input[len]='i'; input[len+1]='e'; input[len+2]='s'; } elseif(input[len]=='s') { input[len+1]='e'; input[len+2]='s'; } elseif(((input[len-1]=='c')&&(input[len]=='h'))) { input[len+1]='e'; input[len+2]='s'; } elseif((input[len-1]=='s')&&(input[len]=='h')) { input[len+1]='e'; input[len+2]='s'; } else { input[len+1]='s'; } printf("\n%s is the plural.",input); return(0); }

Nov 17th, 2005, 10:41 PM	#4
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,466 Rep Power: 8	Change "elseif" to "else if" ... it will compile then. The code needs some work as the plural for "gun" is not "gun" as your program suggests. __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Nov 18th, 2005, 5:51 AM	#5
Blighttdm Newbie Join Date: Oct 2005 Posts: 17 Rep Power: 0	So, why is it not appending any words I enter? Last edited by Blighttdm; Nov 18th, 2005 at 6:05 AM.

Nov 18th, 2005, 6:10 AM	#6
Polyphemus_ Expert Programmer Join Date: Aug 2005 Location: Rotterdam, the Netherlands Posts: 942 Rep Power: 3	This code isn't gonna work, since you don't terminate the string with a 0 character ('\0').

Nov 18th, 2005, 6:16 AM	#7
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	You are not using scanf in such a way as to prevent overrunning the buffer, which can lead to improper operation and crashing of your program. Your buffer, with a length of 30, can hold a 29-character string, maximum, since your string will require a terminating null if you intend to pass it to a C-string function such as printf or strlen. When you overwrite the terminating null that IS there with your plural ending, you're bound to get odd results, if not a memory violation, because you're not terminating your addition. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Nov 18th, 2005, 4:53 PM	#8
Blighttdm Newbie Join Date: Oct 2005 Posts: 17 Rep Power: 0	So how whould I go about fixing this because I'm lost.

Nov 18th, 2005, 5:14 PM	#9
jim mcnamara Hobbyist Programmer Join Date: Jun 2005 Location: New Mexico Posts: 228 Rep Power: 4	Here - I fixed the first block - you can duplicate it down into the other if blocks. (Toggle Plain Text) #include <stdio.h> #include <string.h> int main (void) { char input[30]={0x0}; /* initialize the string / int len=0; printf("Please enter a noun(up to 28 characters) to pluarize:"); fgets(input,sizeof(input),stdin); / prevent user enter LARGE word to crash this program / len=strlen(input); / add an if statment to be sure your word is okay length / len--; / characters start counting from zero, not one so the last character of the string is len-1 -- len-- decrements len / if(input[len]=='y') { input[len]='i'; input[len+1]='e'; input[len+2]='s'; } / it works just fine up to here / #include <stdio.h> #include <string.h> int main (void) { char input[30]={0x0}; / initialize the string / int len=0; printf("Please enter a noun(up to 28 characters) to pluarize:"); fgets(input,sizeof(input),stdin); / prevent user enter LARGE word to crash this program / len=strlen(input); / add an if statment to be sure your word is okay length / len--; / characters start counting from zero, not one so the last character of the string is len-1 -- len-- decrements len / if(input[len]=='y') { input[len]='i'; input[len+1]='e'; input[len+2]='s'; } / it works just fine up to here */

Nov 18th, 2005, 5:22 PM	#10
Blighttdm Newbie Join Date: Oct 2005 Posts: 17 Rep Power: 0	Firstly thanks, Second, I just want to understand how these corrections work. (Toggle Plain Text) fgets(input,sizeof(input),stdin); fgets(input,sizeof(input),stdin); I know gets is used for strings but why use it in a single string? Also stdin, I have no idea what that does, does it involve strings or some type of typical error as a result of gets? (Toggle Plain Text) len--; len--; Why do I have to decrement len? Is it for appending reasons?

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Programming Forums > Application Development > C

String error in if statement