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Jan 1st, 2009

sorting characters in a string... help!!!!

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help.. i dont know how to sort strings.. for example..

if i enter:

C++ Syntax (Toggle Plain Text)

JOKER

then the descending order of string must appear:

C++ Syntax (Toggle Plain Text)

ROKJE

i think of strcpy() ..but it i dont know what to place in the if().. here's my code..

C++ Syntax (Toggle Plain Text)
#include<iostream.h>
#include<conio.h>
#include<string.h>
#include<stdio.h>
void main()
{
   clrscr();
   char a[100],temp[100];
   cout<<"Enter string: ";
   gets(a);
   cout<<"\nThe reverse of the string entered is: ";
   for(int i=(strlen(a)-1);i>=0;i--)
      cout<<a[i];
   cout<<"\n\nLETTERS IN THE STRING: ";
   for(int b=0;b<=(strlen(a)-1);b++)
   {
      for(int c=0;c<=(strlen(a)-2);c++)
      {
	 if(strcmp(a[c],a[c+1])<0) //I DON"T THINK THIS IS RIGHT
	 {
	    strcpy(temp,a[c]);
	    strcpy(a[c],a[c+1]);
	    strcpy(a[c],temp);
	 }
      }
   }
   getch();
}
#include<iostream.h>
#include<conio.h>
#include<string.h>
#include<stdio.h>
void main()
{
   clrscr();
   char a[100],temp[100];
   cout<<"Enter string: ";
   gets(a);
   cout<<"\nThe reverse of the string entered is: ";
   for(int i=(strlen(a)-1);i>=0;i--)
      cout<<a[i];
   cout<<"\n\nLETTERS IN THE STRING: ";
   for(int b=0;b<=(strlen(a)-1);b++)
   {
      for(int c=0;c<=(strlen(a)-2);c++)
      {
	 if(strcmp(a[c],a[c+1])<0) //I DON"T THINK THIS IS RIGHT
	 {
	    strcpy(temp,a[c]);
	    strcpy(a[c],a[c+1]);
	    strcpy(a[c],temp);
	 }
      }
   }
   getch();
}

how could i implement the strcpy or the strcmp in my code??

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scias23

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Jan 1st, 2009

Re: sorting characters in a string... help!!!!

Here is an example to implement strcmp():

int strcmp ( const char * str1, const char * str2 );

<cstring>

Compare two strings

Compares the C string str1 to the C string str2.
This function starts comparing the first character of each string. If they are equal to each other, it continues with the following pairs until the characters differ or until a terminanting null-character is reached.

Parameters

str1
C string to be compared.
str2
C string to be compared.

Return Value
Returns an integral value indicating the relationship between the strings:
A zero value indicates that both strings are equal.
A value greater than zero indicates that the first character that does not match has a greater value in str1 than in str2; And a value less than zero indicates the opposite.

Example

/* strcmp example */
#include <stdio.h>
#include <string.h>

int main ()
{
char szKey[] = "apple";
char szInput[80];
do {
printf ("Guess my favourite fruit? ");
gets (szInput);
} while (strcmp (szKey,szInput) != 0);
puts ("Correct answer!");
return 0;
}

Output:

Guess my favourite fruit? orange
Guess my favourite fruit? apple
Correct answer!

Jenniferlinn

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Jan 1st, 2009

Re: sorting characters in a string... help!!!!

Look, you have that #include<string.h> right? So why don't you use c++ strings? It's like

CPP Syntax (Toggle Plain Text)

string str;
str = "whatever"

and it's easier.
Now this

CPP Syntax (Toggle Plain Text)
 
for(int b=0;b<=(strlen(a)-1);b++)
   {
      for(int c=0;c<=(strlen(a)-2);c++)
      {
	 if(strcmp(a[c],a[c+1])<0) //I DON"T THINK THIS IS RIGHT
	 {
	    strcpy(temp,a[c]);
	    strcpy(a[c],a[c+1]);
	    strcpy(a[c],temp);
	 }
      }
   }
  
for(int b=0;b<=(strlen(a)-1);b++)
   {
      for(int c=0;c<=(strlen(a)-2);c++)
      {
	 if(strcmp(a[c],a[c+1])<0) //I DON"T THINK THIS IS RIGHT
	 {
	    strcpy(temp,a[c]);
	    strcpy(a[c],a[c+1]);
	    strcpy(a[c],temp);
	 }
      }
   }

is a mess. You could just compare a[c] < a[c+1] cuz this are characters, not strings and they are already sorted in ASCII.

Could you please explain what the program is supposed to do?

da penguin

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Jan 1st, 2009

Re: sorting characters in a string... help!!!!

Click to Expand / Collapse Quote originally posted by da penguin ...

Look, you have that #include<string.h> right? So why don't you use c++ strings? It's like
CPP Syntax (Toggle Plain Text)
string str;
str = "whatever"
string str; str = "whatever"
and it's easier.
Now this
CPP Syntax (Toggle Plain Text)
 
for(int b=0;b<=(strlen(a)-1);b++)
   {
      for(int c=0;c<=(strlen(a)-2);c++)
      {
	 if(strcmp(a[c],a[c+1])<0) //I DON"T THINK THIS IS RIGHT
	 {
	    strcpy(temp,a[c]);
	    strcpy(a[c],a[c+1]);
	    strcpy(a[c],temp);
	 }
      }
   }
for(int b=0;b<=(strlen(a)-1);b++) { for(int c=0;c<=(strlen(a)-2);c++) { if(strcmp(a[c],a[c+1])<0) //I DON"T THINK THIS IS RIGHT { strcpy(temp,a[c]); strcpy(a[c],a[c+1]); strcpy(a[c],temp); } } }
is a mess. You could just compare a[c] < a[c+1] cuz this are characters, not strings and they are already sorted in ASCII.

Could you please explain what the program is supposed to do?

okay, the program should sort the characters in a string in descending order.. for example.. if i cin yahoo, the program should cout yooha.. there..

Last edited by scias23; Jan 1st, 2009 at 9:04 am. Reason: for clarification

scias23

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Jan 1st, 2009

Re: sorting characters in a string... help!!!!

Introducing bubble sort

CPP Syntax (Toggle Plain Text)
#include <iostream>
#include <string>
 
int main()
{
	std::string str;
	std::cin >> str;
 
	char tmp;
 
	int i,j;
	for(i=0;i<str.size()-1;++i) {
		for(j = i+1;j<str.size();++j) {
			if(str[i] < str[j])
			{
				tmp = str[i];
				str[i] = str[j];
				str[j] = tmp;
			}
		}
	}
 
	std::cout << str;
 
	return 0;
}
#include <iostream>
#include <string>

int main()
{
	std::string str;
	std::cin >> str;

	char tmp;

	int i,j;
	for(i=0;i<str.size()-1;++i) {
		for(j = i+1;j<str.size();++j) {
			if(str[i] < str[j])
			{
				tmp = str[i];
				str[i] = str[j];
				str[j] = tmp;
			}
		}
	}

	std::cout << str;

	return 0;
}

This works.

da penguin

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Jan 1st, 2009

Re: sorting characters in a string... help!!!!

THANK YOU VERY MUCH!!! IT WORKS!! but can you please explain to me how this code works.?

scias23

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Jan 1st, 2009

Re: sorting characters in a string... help!!!!

Well, i just transformed your own code. Used string str instead of char* a[100] and char tmp instead of char* tmp[100] (u need just one character to bubble-sort, not an array).
You would like to use strings in c++ instead of char arrays in cases like this, because it's much easier to do so. Like you can write string1 = string2 instead of strcpy.
that's all

da penguin

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Jan 1st, 2009

Re: sorting characters in a string... help!!!!

Thanks sa penguin!!!

scias23

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Jan 1st, 2009

Re: sorting characters in a string... help!!!!

help here again... if i enter AaBbCc the output should be CcBbAa or cCbBaA.. but the output appears cbaCBA.. help!!! heres the code..

(Toggle Plain Text)

#include<iostream.h>
#include<conio.h>
#include<string.h>
#include<stdio.h>
#include<search.h>
//int joke(const void* x,const void* y);
void main()
{
   clrscr();
   char a[100],temp;
   cout<<"Enter string: ";
   cin>>a;
   for(int i=(strlen(a)-1);i>=0;i--)
      cout<<a[i];
   cout<<"\n\nLETTERS IN THE STRING: ";
   for(int b=0;b<(strlen(a)-1);b++)
   {
      for(int c=b+1;c<(strlen(a));c++)
      {
	 if(a[b]<a[c])
	 {
	    temp=a[b];
	    a[b]=a[c];
	    a[c]=temp;
	 }
      }
   }
   cout<<a;
   getch();
}

scias23

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Jan 1st, 2009

Re: sorting characters in a string... help!!!!

Click to Expand / Collapse Quote originally posted by scias23 ...

help here again... if i enter AaBbCc the output should be CcBbAa or cCbBaA.. but the output appears cbaCBA.. help!!! heres the code..

if(a[b]<a[c])

If that's the goal, then this line won't work for your purposes. Any lower case letter has a higher ASCII value than an upper case letter. The < operator uses the ASCII table. You need to use toupper or tolower in the line above to convert the digits from upper to lower case or vice versa and handle the comparison.

http://www.cplusplus.com/reference/c...e/toupper.html
http://www.cplusplus.com/reference/c...e/tolower.html

VernonDozier

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