Problem With strings

[Unregistered]

I am trying to get this program to work for me and I believe I am missing a few things. The program will ask the user to enter a string or sentence up to 50 or more characters. Then it will re print what the user has inputted in lines of 30-35. Then it will prompt the user to pick a letter and it will find how many letters are in that string or sentence... Here is what I have so far.

//this program is to make a long line of text look
//more presentable to the user.

#include<stdio.h>
#include<string.h>
#define linelen 30

void main (void)
{
int string_length;
int count;
char text[80];
char line[linelen];
printf("\nPlease Enter a long line of text(Greater than 50 characters):\n");
gets(text);
string_length=strlen(text);

for(count=0;count<string_length;count++)
{
if(line[strlen(line) - 1]=='\n');
printf("%c\n\n",line);
}
printf("\n The Length of the string is: %d", string_length);

}

[C_Coder]

Your using the array line without putting anything in it.

this will put linelen characters in line

strncpy(line, text_ptr, linelen);

you need to use a pointer to text which you can then point to the next line by doing

text_ptr += linelen;

then you can print the line

printf("%s", line);

then you can start the loop again.

while(*text_ptr){
     strncpy(line, text_ptr, linelen);
     text_ptr += linelen;
     printf("%s", line);
}
printf("\nLength of string is %d", strlen(text));

[C_Coder]

I forgot to put a newline in

while(*text_ptr){
     strncpy(line, text_ptr, linelen);
     text_ptr += linelen;
     printf("\n%s", line);
}
printf("\nLength of string is %d", strlen(text));

That should do the trick

[quzah]

You may want to change this slightly. If you have less than linelen, and you add linelen to text_ptr, you'll blow past the end of your string.

while(*text_ptr){
     x = strncpy(line, text_ptr, linelen);
     if( x > -1 )
        text_ptr += x;
     else
        text_prt = NULL;
     printf("\n%s", line);
}
printf("\nLength of string is %d", strlen(text));

Try that.

Quzah.

[Unregistered]

I tried it and know I am getting more errors. Please bear with me I am very new at this....

#include<string.h>
#define linelen 30

void main (void)
{
int string_length;
int count;
char text[80],text_ptr;
char line[linelen];
printf("\nPlease Enter a long line of text(Greater than 50 characters):\n");
gets(text);
string_length=strlen(text);

while(*text_ptr)
{
strncpy(line, text_ptr, linelen);
text_ptr += linelen;
printf("\n%s", line);
}
printf("\nLength of string is %d", strlen(text));
}

[quzah]

char text[80],text_ptr;

1) text_ptr is not a pointer here.

char text[80], *text_ptr;

Now it is.

2) You never assign 'text_ptr' to anything.

Quzah.

[Unregistered]

Still isn't workin.Know it seems to go into an infinite loop!!!


void main (void)
{
int string_length;
int count;
char text[80],*text_ptr;
char line[linelen];
printf("\nPlease Enter a long line of text(Greater than 50 characters):\n");
gets(text);
string_length=strlen(text);

while(*text_ptr)
{
strncpy(line, text_ptr, linelen);
text_ptr += linelen;
printf("\n%s", line);
}
printf("\nLength of string is %d", strlen(text));
}

[quzah]

> > while(*text_ptr)
> Do this while text_ptr is pointing at a non-nul character (\0).
> Meaning if you jump more than one character at once, you
> stand a good chance of missing the \0 altogether.

Well, yeah, there is that, but...

> char text[80],*text_ptr;
> char line[linelen];
> printf("\nPlease Enter a long line of text(Greater than 50 characters):\n");
> gets(text);
> string_length=strlen(text);
>
> while(*text_ptr)
> {
> strncpy(line, text_ptr, linelen);

Then of course, there is THIS LITTLE PROBLEM, that I keep telling you (the original poster) about. "text_prt" has no value assigned. Variables in C -- unless static -- are NOT initialized with a value. It is possible that your loop will outright fail without ever doing ANYTHING, because "text_prt" will hold some random value because you never assign it to anything.

ALWAYS ALWAYS ALWAYS assign pointers a value before dereferencing them!

Additionaly:

strncpy( line, text_prt, linelen )

WHAT? You're copying a portioin of your line to AN UNINITIALIZED POINTER. Sigh... I give up. How much clearer do I have to make this?

Quzah.