Reading strings input by the user...

Cmuppet · 07-16-2004, 04:26 PM

I've done a search and came up with nothing helpful....

I have been stuck at this for a few day's now , I need too write a program that will use scanf() to read in seven strings input by the user. The program should print the seven strings as a list , then sort them alphabettically and print a new list.

I need to use the function strcmp() , & the preprocessing directive #define N_STRINGS 7 to assist in the sorting of the strings

I have tried using for loops & while loops with scanf() in reading in the strings , & then printing it out but im all ready stuck

At this point im just trying to get my code to read 7 strings input by the user & just print them out again.
This is what i've come up with sofar but it's not working at all & very long .

Code:

#include <stdio.h>
#include <string.h>
#define N_STRINGS 7
#define SIZE 100
#define SIZED 700

void main(int argc)
{
  char c;
  int i;
  int count = 0;
  char array1[SIZE];
  char array2[SIZE];
  char array3[SIZE];
  char array4[SIZE];
  char array5[SIZE];
  char array6[SIZE];
  char array7[SIZE];
  
  printf("Type in 7 strings...\n\n");
  if (argc < SIZED){
	  while ((c = getchar()) != '\n'){
	      scanf("%s", array1);
	      count++;
	  }
	   array1[count - 1] = '\0';
	   count = 0;
	   while ((c = getchar()) != '\n'){
		   scanf("%s", array2);
		   count++;
	   }
	   array2[count - 1] = '\0';
	   count = 0;
	   while ((c = getchar()) != '\n'){
		   scanf("%s", array3);
		   count++;
	   }
	   array3[count - 1] = '\0';
	   count = 0;
	   while ((c = getchar()) != '\n'){
		   scanf("%s", array4);
           count++;
	   }	    
	   array4[count - 1] = '\0';
	   count = 0;
	   while ((c = getchar()) != '\n'){
		   scanf("%s", array5);
		   count++;
	   }
	   array5[count - 1] = '\0';
	   count = 0;
	   while ((c = getchar()) != '\n'){
		   scanf("%s", array6);
		   count++;
	   }
	   array6[count - 1] = '\0';
	   count = 0;
	   while ((c = getchar()) != '\n'){
		   scanf("%s", array7);
		   count++;
	   }
	   array7[count - 1] = '\0';
  }
  else {
	  printf("Type in 7 strings...\n");
  }
  printf("\n");
  printf("Printing the strings again ...\n");
  for (i = 0;(c = getchar()) != '\0';++i){
	  printf("%s",array1[i]);
  }
  for (i = 0;(c = getchar()) != '\0';++i){
	  printf("%s",array2[i]);
  }
  for (i = 0;(c = getchar()) != '\0';++i){
	  printf("%s",array3[i]);
  }
  for (i = 0;(c = getchar()) != '\0';++i){
	  printf("%s",array4[i]);
  }
  for (i = 0;(c = getchar()) != '\0';++i){
	  printf("%s",array5[i]);
  }
  for (i = 0;(c = getchar()) != '\0';++i){
	  printf("%s",array6[i]);
  }
  for (i = 0;(c = getchar()) != '\0';++i){
	  printf("%s",array7[i]);
  }
  

}

Thanks a lot for any help

Btw I must use scanf() in reading in the strings it says so in my textbook .

Robc · 07-16-2004, 04:41 PM

>void main(int argc)
This is way wrong. First, main returns int. Second, the only two portable definitions take 0 and 2 arguments. Third, you aren't using argc correctly.

It's better to leave the implementation to the nitty gritty details at this stage. Study the following and incorporate what you learn into your own code. You'll probably need to replace qsort with your own custom sorting routine though. Most teachers don't like you to use it.

Code:

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

#define N_STRINGS 7

int cmp(const void *a, const void *b);

int main(void)
{
  /* Declare an array of strings */
  char strings[N_STRINGS][BUFSIZ];
  int  i;

  /* Read N_STRINGS strings */
  for (i = 0; i < N_STRINGS; i++) {
    /* A prompt is always helpful to users */
    printf("Enter string %%%d: ", i + 1);
    /* Unless you print a '\n' in the prompt, you need this */
    fflush(stdout);
    /* ALWAYS check scanf for success */
    if (scanf("%s", strings[i]) != 1) {
      fprintf(stderr, "Error reading input\n");
      return EXIT_FAILURE;
    }
  }
  /* Sort the array using cmp as the comparison routine */
  qsort(strings, N_STRINGS, sizeof strings[0], cmp);
  /* Print out the sorted result */
  for (i = 0; i < N_STRINGS; i++) {
    printf("%s\n", strings[i]);
  }

  return EXIT_SUCCESS;
}

int cmp(const void *a, const void *b)
{
  return strcmp((const char *)a, (const char *)b);
}

Emmanuel Delaha · 07-16-2004, 04:50 PM

Quote:

Originally Posted by Cmuppet

This is what i've come up with sofar but it's not working at all & very long .

You should learn how to configure your compiler to say more about your coding :

Code:

Compilateur: Default compiler
Building Makefile: "D:\Dev-Cpp\Makefile.win"
Exécution de  make...
make.exe -f "D:\Dev-Cpp\Makefile.win" all
gcc.exe -D__DEBUG__ -c main.c -o main.o -I"C:/DEV-CPP/include" -W -Wall -O2   -g3

main.c:8: warning: return type of `main' is not `int'
main.c:8: warning: `main' takes only zero or two arguments

main.c: In function `main':
main.c:70: warning: format argument is not a pointer (arg 2)
main.c:73: warning: format argument is not a pointer (arg 2)
main.c:76: warning: format argument is not a pointer (arg 2)
main.c:79: warning: format argument is not a pointer (arg 2)
main.c:82: warning: format argument is not a pointer (arg 2)
main.c:85: warning: format argument is not a pointer (arg 2)
main.c:88: warning: format argument is not a pointer (arg 2)

gcc.exe -D__DEBUG__ main.o  -o "Projet1.exe" -L"C:/DEV-CPP/lib" C:/Dev-Cpp/lib/libws2_32.a -g3 

Exécution terminée
Compilation OK

Cmuppet · 07-16-2004, 05:10 PM

Thanks for the replies guys. I was assuming the user entering a string though could enter more than one word at a time & the string would end only when the user hits enter ??

Robc · 07-16-2004, 05:59 PM

>I was assuming the user entering a string though could enter more than one word at a
>time & the string would end only when the user hits enter ??
That's not how scanf works. Parsing only goes to the next whitespace with the %s specifier. That means that words will be split up. Fortunately, this is easy to fix, but unfortunately, it's difficult to get right.

Code:

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

#define N_STRINGS 7

int cmp(const void *a, const void *b);

int main(void)
{
  /* Declare an array of strings */
  char strings[N_STRINGS][1024];
  int  i;

  /* Read N_STRINGS strings */
  for (i = 0; i < N_STRINGS; i++) {
    /* A prompt is always helpful to users */
    printf("Enter string %%%d: ", i + 1);
    /* Unless you print a '\n' in the prompt, you need this */
    fflush(stdout);
    /* ALWAYS check scanf for success */
    /* The [^\n] specifier says to read until '\n' is found */
    if (scanf("%1024[^\n]", strings[i]) != 1) {
      fprintf(stderr, "Error reading input\n");
      return EXIT_FAILURE;
    }
    /* scanf leaves '\n' in the stream, so we have to remove it */
    getchar();
  }
  /* Sort the array using cmp as the comparison routine */
  qsort(strings, N_STRINGS, sizeof strings[0], cmp);
  /* Print out the sorted result */
  for (i = 0; i < N_STRINGS; i++) {
    printf("%s\n", strings[i]);
  }

  return EXIT_SUCCESS;
}

int cmp(const void *a, const void *b)
{
  return strcmp((const char *)a, (const char *)b);
}

Even that's not perfect, but it'll be more than enough for your purposes.

In general, it's a bad idea to use scanf for string data. fgets is better suited to that task.

Cmuppet · 07-18-2004, 09:10 PM

Thanks again for your help Robc

**Hammer** · 07-19-2004, 03:26 PM

http://faq.cprogramming.com/cgi-bin/...&id=1043284385

Cmuppet · 07-21-2004, 03:47 AM

Oke i've come up with this code , & i've been paining my brain trying to figure out why it's not working. Im guessing it's an array overflow somewhere somehow ???

Thanks again for helping !!

Code:

#include <stdio.h>
#include <string.h>
#define N_STRINGS 7
#define SIZE 15

void main(void)
{
  int i,j,compare;
  char arrays[N_STRINGS][SIZE];
  char sortedarray[N_STRINGS][SIZE];

  for (i = 0;i < N_STRINGS;++i){
	  printf("Enter string %d : ",i);
      scanf("%s",arrays[i]);
  }
  printf("Printing the strings again ...\n");
  for (i = 0;i < N_STRINGS;++i){
	  printf("\n%s\n",arrays[i]);
  }
  printf("Sorting the strings...\n");

  for (i = 0;i < N_STRINGS;++i){
	  for (j = 0;j < SIZE;++j){
	    compare = strcmp(&arrays[i][j],&arrays[i + 1][j]);
	    if ((compare == -1)||(compare == 0)){
		  sortedarray[i][j] == arrays[i][j];
		  sortedarray[i + 1][j] == arrays[i + 1][j];
	    }
	    else{
                  sortedarray[i][j] == arrays[i + 1][j];
                  sortedarray[i + 1][j] == arrays[i][j];
	    }
	  }
	 
  }
  printf("Printing the strings again sorted this time...\n");
  for (i = 0;i < N_STRINGS;++i){
	  for (j = 0;j < SIZE;++j)
		  printf("%s",sortedarray[i][j]);
	  
  }
}

int strcmp(const char *s1,const char *s2){
     return (*s1,*s2);
}

Emmanuel Delaha · 07-21-2004, 04:24 AM

Quote:

Originally Posted by Cmuppet

Oke i've come up with this code , & i've been paining my brain trying to figure out why it's not working. Im guessing it's an array overflow somewhere somehow ???

Thanks again for helping !!

Starts weirdly...

Code:

Compiling MAIN.C:
Error MAIN.C 7: main must have a return type of int
Warning MAIN.C 31: Code has no effect
Warning MAIN.C 32: Code has no effect
Warning MAIN.C 36: Code has no effect
Warning MAIN.C 37: Code has no effect
Warning MAIN.C 54: Parameter 's1' is never used

Quote:

Code:

	    if ((compare == -1)||(compare == 0)){
		  sortedarray[i][j] == arrays[i][j];
		  sortedarray[i + 1][j] == arrays[i + 1][j];
	    }
	    else{
                  sortedarray[i][j] == arrays[i + 1][j];
                  sortedarray[i + 1][j] == arrays[i][j];
	    }

My compiler is correct. These four '==' are weird ! You meant '=', of course...

Quote:

Code:

int strcmp(const char *s1,const char *s2){
     return (*s1,*s2);
}

Huh! Why in the world are you attempting to redefine strcmp() ? Just drop these three lines.

I don't pretend that this will fix all your bugs, but it's a start.

quzah · 07-21-2004, 04:31 AM

Quote:

Originally Posted by Emmanuel Delahaye

Huh! Why in the world are you attempting to redefine strcmp() ? Just drop these three lines.

I'm not saying I'd recommend it, but you're allowed to do so if you so desire...

[edit]
Although, their implementation ... leaves much to be desired.

After a second, it's probably a bad idea to include "string.h" in attempting to do so...

[/edit]

Quzah.

Cmuppet · 07-21-2004, 05:54 AM

oh dear my brain must have been fried lol , using == instead of =
thanks for pointing that out , i overlooked it completly

Cmuppet · 07-21-2004, 05:58 AM

Im still getting an error message

Cmuppet · 07-21-2004, 06:02 AM

Thanks btw for pointing these things out to me

**Salem** · 07-21-2004, 06:37 AM

Well post your latest code and actual error messages then

07-16-2004, 05:10 PM	#4
Cmuppet Registered User Join Date: Jul 2004 Posts: 46	Thanks for the replies guys. I was assuming the user entering a string though could enter more than one word at a time & the string would end only when the user hits enter ??
Cmuppet is offline

07-18-2004, 09:10 PM	#6
Cmuppet Registered User Join Date: Jul 2004 Posts: 46	Thanks again for your help Robc
Cmuppet is offline

07-19-2004, 03:26 PM	#7
Hammer End Of Line Join Date: Apr 2002 Posts: 6,240	http://faq.cprogramming.com/cgi-bin/...&id=1043284385 __________________ When all else fails, read the instructions. If you're posting code, use code tags: [code] /* insert code here */ [/code]
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07-21-2004, 05:54 AM	#11
Cmuppet Registered User Join Date: Jul 2004 Posts: 46	oh dear my brain must have been fried lol , using == instead of = thanks for pointing that out , i overlooked it completly
Cmuppet is offline

07-21-2004, 05:58 AM	#12
Cmuppet Registered User Join Date: Jul 2004 Posts: 46	Im still getting an error message
Cmuppet is offline

07-21-2004, 06:02 AM	#13
Cmuppet Registered User Join Date: Jul 2004 Posts: 46	Thanks btw for pointing these things out to me
Cmuppet is offline

07-21-2004, 06:37 AM	#14
Salem and the hat of vanishing Join Date: Aug 2001 Location: The edge of the known universe Posts: 21,214	Well post your latest code and actual error messages then __________________ If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut. Up to 8Mb PlusNet broadband from only £5.99 a month!
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