error in my code

There is a mismatch in your declaration and your definition of encrypt function. The definition (last line) is probably what you want.

void encrypt(char *plain_text);
encrypt(plain_text);
void encrypt( char *plain_text,char *encrypted_text)

Select allOpen in new window

You usage
       encrypt(plain_text);
probably should be
       encrypt(plain_text, encrypted_text )

Also,
    decrypt(*encrypted_text);
should be
   decrypt(encrypted_text);
since encrypted_text (after you uncomment it) is actually a constant pointer to the starting address of the encrypted_text array.

Hi

I have done as you suggested but still get the same error
c|8|error: expected initializer before "void"|
c||In function `int main()':|
c|37|error: `display_file' was not declared in this scope|
.c|50|error: `encrypted_text' was not declared in this scope|
.c|50|error: `encrypt' was not declared in this scope|
.c|58|error: `encrypted_text' was not declared in this scope|
||=== Build finished: 5 errors, 0 warnings ===|

#include <stdio.h>
#include <stdlib.h>
#define MAX_CHARACTERS 81
#include <string.h>
void encrypt( char *plain_text,char *encrypted_text)


void display_file();
void show_one_line();
void last_n_lines();
void decrypt(char *encrypted_text);
void text_analysis();
int menu();

#define SIZE 20
  char plain_text[20+1];
  //char encrypted_text[20+1];



int option;


int main()
{


	do
	{
		option=menu();

		switch (option)
		{
			case 0:
				break;
			case 1:
				display_file();
				break;
			case 2:
				show_one_line();
				break;
			case 3:
				last_n_lines();
				break;
            case 4:
				{
				printf("Enter your file name: ");
				scanf("%s",plain_text);
				//shift=get_encryption_key();
				encrypt(plain_text, encrypted_text );
				printf("File name:%s\n", plain_text);
				printf("Encrypted file name:%s\n", encrypted_text);
				break;
				}

            case 5:
				{
					decrypt(encrypted_text);
					printf("Decrypted back Plain Text:%s\n", plain_text);
				}

				break;
            case 6:
				text_analysis();
				break;
		}
	}
    while (option!=0);
	return 0;
}

int menu()
{
    int opt;
    printf("\n");
    printf ("1. Display the file \n");
    printf ("2. Display any line in the file \n");
    printf ("3. Display the last n lines in the file \n");
    printf ("4. Encrypt the file using the Caesar Cypher \n");
    printf ("5. Decrypt the fle using the Caesar Cypher \n");
    printf ("6. Display a text analysis of the file \n");
    printf ("0. Exit\n\n");
    scanf  ("%d",&opt);
    printf("\n");
    return opt;
}

//Function 1 to display the File DT249.txt//
void display_file(void)
{
	FILE* fp_in ;
	char one_line[ MAX_CHARACTERS ] ;
	char show_no = 'N', cont_line = 'C', Y, N, C, Q;/* Array used to store line */
	int line_number=1;


	/* Open the file for reading */
	if ( (fp_in=fopen("DT249.txt", "r") ) == NULL )
		puts( "Error in opening DT249.txt" ) ;
	else
	{
		printf("do you want to display the line number? type Y for yes or N for No");
	    // using getchar()
		fflush(stdin);
		Y = getchar();
		if (show_no == Y || 'n' == Y)
            {
				while( fgets( one_line, MAX_CHARACTERS, fp_in )!=NULL )
					if(feof(fp_in))
					{
						printf( "%s",  one_line ) ;
						printf( "%s",  "No more contents to read") ;
						return;
					}
					else
						printf( "%s",  one_line ) ;

			}
            else if (show_no == Y || 'y' == Y)
			{
				while( fgets( one_line, MAX_CHARACTERS, fp_in )!=NULL )
					if(feof(fp_in))
					{
						printf( "Line Number : %d \n %s",  line_number,one_line ) ;
						printf( "%s",  "No more contents to read \n") ;
						line_number++;
						return;
					}
					else
					{
						printf( "Line Number : %d \n %s",  line_number,one_line ) ;
						line_number++;
					}

			}


		fclose( fp_in ) ;
	}
}

//Function 2 to display one line from the text//

void show_one_line(void)
{
	FILE* fp_in ;
	char one_line[ MAX_CHARACTERS ] ;/* Array used to store line */
	int line_number=1;
	int line_count=1;


	/* Open the file for reading */
	if ( (fp_in=fopen("DT249.txt", "r") ) == NULL )
		puts( "Error in opening DT249.txt" ) ;
	else
	{
		printf("enter the no of lines from the end you want to see ");
		scanf("%d", &line_number);
		/* Read at most MAX_CHARACTERS-1 characters from the file
		 or until a new line character (\n) is read
		 or the end of file occurs. */
		while( fgets( one_line, MAX_CHARACTERS, fp_in )!=NULL )
		{
			if (line_number==line_count)
				printf( "%d.%s", line_count, one_line ) ;
			//if (line_number==line_count)
			line_count ++;
		}
		fclose( fp_in ) ;
	}

}

//Function 3 to display n lines from the end from the text file//
void last_n_lines(void)
{
	FILE* fp_in ;
	char n_line[ MAX_CHARACTERS ] ;/* Array used to store line */
	int line_number=0;
	int line_count=0;
	int line_print = 0;

	/* Open the file for reading */
	if ( (fp_in=fopen("DT249.txt", "r") ) == NULL )
		puts( "Error in opening DT249.txt" ) ;
	else
	{
		printf("enter the no of lines you want to see from the end");
		scanf("%d", &line_number);

		while( fgets( n_line, MAX_CHARACTERS, fp_in )!=NULL )
		{
			line_count ++;
		}

		if (line_count > line_number)
			line_print = line_count - line_number;

		 fseek(fp_in, 0, SEEK_SET);
		line_count = 0;
		while( fgets( n_line, MAX_CHARACTERS, fp_in )!=NULL )
		{
			if (line_count >= line_print)
				printf( "%d.%s", line_count, n_line ) ;
			line_count ++;
		}
		fclose( fp_in ) ;
	}
}


//Function 4 to encrypt a text file using the Caesar Cypher//

void encrypt( char *plain_text,char *encrypted_text)
{
  char ch;
  int i=0;
  int len=strlen(plain_text);
  for (i=0;i<len;i++)
  {
    ch=plain_text[i];
    if (ch<='Z' && ch>='A')  /* shift upper case letters */
      encrypted_text[i]  = (ch -'A'+ 3 )%26+'A' ;
    else if (ch<='z' && ch>='a')  /* shift lower case letters */
      encrypted_text[i]  = (ch -'a'+ 3 )%26+'a' ;
    else  /* all other characters are not encrypted */
      encrypted_text[i] =ch ;
  }
  encrypted_text[i] = '\0';
}



//Function 5 to decrypt a text file using the Caesar Cypher//
void decrypt(char *encrypted_text)
{
  char ch;
  int i=0;
  int len;  /* number of characters*/

  len = strlen(encrypted_text);

  for (i=0;i<len;i++)
  {

    ch=encrypted_text[i];

    if (ch<='Z' && ch>='A')  /* shift upper case letters */
      plain_text[i]  = (ch +'A'-3 )%26+'A' ;
    else if (ch<='z' && ch>='a')  /* shift lower case letters */
      plain_text[i]  = (ch +'a'-3 )%26+'a' ;
    else  /* all other characters are not decrypted */
      plain_text[i] =ch ;
  }
  plain_text[i] = '\0';
}

//Function 6 to carry out text analysis on file DT249.txt//

void text_analysis()
{

}

Select allOpen in new window

As evilrix mentioned, is the comment here intentional?
>>     //char encrypted_text[20+1];

thanks

The actual problem in question was solved by the first post!

http:#32036400

error in line 62 saying |error: `encrypted_text' was not declared in this scope

"Line 21 -- is that meant to be commented out?"

//char encrypted_text[20+1]; //<--- this is commented out so the compiler cannot see it!

>> The actual problem in question was solved by the first post!
Yes, true. I didn't see the first post when I made my post. So, an adjustment of the accept is in order.

Thanks phoffric.

Hi

Apologies for that i clicked on the wrong post by accident and didnt realise it until now.

No worries. Thanks.

As with most questions regarding compilation errors, often there are multiple errors that all get resolved before a question is closed. After removing the comment line 21 in original post, there were still compilation errors that needed to be addressed (since as seen the author did post follow-up questions with the intent of resolving all the compilation errors).

For this reason, to capture all the compilation errors, recommend that http:#32036826 be accepted, as well as http:#32037095, and http:#32037962, and http:#32036400

Hi , Again you have simple and mistakes by ignorance.
First you should have ; at the end of method declaration. It should be

void encrypt( char *plain_text,char *encrypted_text);
Instead of
void encrypt( char *plain_text,char *encrypted_text)

Also as it has been mentioned that you need to un comment follwoing
//char encrypted_text[20+1];
it should be
char encrypted_text[20+1];