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Strings and For Loops

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Join Date: Apr 2005

Posts: 3

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Starz20

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Newbie Poster

Strings and For Loops

Apr 9th, 2005

Hello everyone. My instructor has asked me to write a program that accepts a string as input from a user and prints the string in reverse. I have to use a "for" loop to reverse the string. I am also suppose to allow the user to input more than one string. I think I have done a pretty job at all of the above except for allowing the user to input an additional string. I am taking an intro to C++ and am very new to C++. In the program I have done so far I have defined a character limit of 256. I am confused on how to alow the user to input an additional string. I am not really for sure where to justify this in the body of the program or if it has to be done in the beginning. Any help would be greatly appreciated.

I was thinking it would be here, but I changed the value it did not work.
for (i=0; i<length; i++)

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#include  <stdio.h> 
#include  <stdlib.h> 
#include  <string.h>
#define MAXLINE 256
int main(void) 
	
{ 
  
     char str[MAXLINE], rev[MAXLINE];
     int i, length;
    
     /*--------------------------------------------
     *  Read string and determine length  
     *--------------------------------------------*/
     printf("Enter string:    ");
     scanf ("%s", str);
     length= strlen(str);
     /*---------------------------------------------
     *  Build the reversed string and print it.
     * Don't forget to add the terminating 0!
     *---------------------------------------------*/
      	/* loop 2 times */ this did not help
      for (i=0; i<length; i++) 
   rev[length-i-1] = str[i];
     rev[length] = 0;
     printf("reverse string:  %s\n\n", rev);
     /*---------------------------
     *  Palindrome?
     *---------------------------*/
     if (strcmp (str,rev) == 0) 
   printf ("Palindrome!\n\n");
     else
   printf ("Not a Palindrome\n\n");
     return 0; 
}

Code tags added. -Narue

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Join Date: Sep 2004

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Narue

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Code Goddess

Re: Strings and For Loops

Apr 9th, 2005

Throw the whole thing in a loop and break from the loop if the user enters something that isn't valid:

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#include  <stdio.h> 
#include  <stdlib.h> 
#include  <string.h>
#define MAXLINE 256
int main(void) 
{ 
  char str[MAXLINE], rev[MAXLINE];
  int i, length;
 
  for ( ; ; ) {
    /*--------------------------------------------
    *  Read string and determine length  
    *--------------------------------------------*/
    printf("Enter string or EOF to quit:    ");
    if ( scanf ("%s", str) != 1 )
      break;
    length = strlen(str);
    /*---------------------------------------------
    *  Build the reversed string and print it.
    * Don't forget to add the terminating 0!
    *---------------------------------------------*/
    for (i=0; i<length; i++) 
      rev[length-i-1] = str[i];
    rev[length] = 0;
    printf("reverse string:  %s\n\n", rev);
    /*---------------------------
    *  Palindrome?
    *---------------------------*/
    if (strcmp (str,rev) == 0) 
      printf ("Palindrome!\n\n");
    else
      printf ("Not a Palindrome\n\n");
  }
 
  return 0; 
}
#include  <stdio.h> 
#include  <stdlib.h> 
#include  <string.h>
#define MAXLINE 256
int main(void) 
{ 
  char str[MAXLINE], rev[MAXLINE];
  int i, length;

  for ( ; ; ) {
    /*--------------------------------------------
    *  Read string and determine length  
    *--------------------------------------------*/
    printf("Enter string or EOF to quit:    ");
    if ( scanf ("%s", str) != 1 )
      break;
    length = strlen(str);
    /*---------------------------------------------
    *  Build the reversed string and print it.
    * Don't forget to add the terminating 0!
    *---------------------------------------------*/
    for (i=0; i<length; i++) 
      rev[length-i-1] = str[i];
    rev[length] = 0;
    printf("reverse string:  %s\n\n", rev);
    /*---------------------------
    *  Palindrome?
    *---------------------------*/
    if (strcmp (str,rev) == 0) 
      printf ("Palindrome!\n\n");
    else
      printf ("Not a Palindrome\n\n");
  }

  return 0; 
}