Standard C++ Generic Algorithm 'next_permutation()'

[whodgson]

The example of this algorithm is taken from the book I'm learning from.
It compiles but won't run. Can anyone see what's wrong?

#include<iostream>
#include<algorithm>
//have also included <cmath> and <cstdlib> to no affect.
using namespace std;
 
int main()
{
    char* s="ABCD";
    for(int i=0;i<24;i++)
    { next_permutation(s,s+4);
    cout<<(i%8?'\t':'\n')<<s;
    }
system("pause");
return 0;
 
}

//output is meant to be:-
ABDC ACBD ACDB etc ..to ABCD ie(.until all 24 combinations
are printed.)
Appreciate any thoughts.

[oler1s]

Define, "won't run".

[newb16]

"abcd" is constant ( eg a string within executable code ) and is not supposed to be changed. Copy it to some other string beforehand.

[whodgson]

oler1s
'won't run' means (loosely) that when the IDE Bloodshed Dev C++(v 4.9.9.2) runs the .exe file the monitor screen changes to a black DOS screen and after a few second back to the IDE screen whereupon a Windows message box appears which says:
"next_permutation.exe has encountered a problem and needs to close. We are sorry for the inconvenience." It offers to tell Microsft about the problem.
newb16
I will grapple with your solution.

[whodgson]

Thanks -- this is how it ended up
//30/09/08 17:03

#include<iostream>
#include<algorithm>
using namespace std;
 
int main()
{char A,B,C,D;
    char s[4]={'A','B','C','D'};
     for(int i=0;i<24;i++)
     {next_permutation(s,s+4);
     cout<<s[0]<<s[1]<<s[2]<<s[3]<<" ";
     if(i==7||i==15)cout<<"\n";
     }
cout<<endl;
system("pause");
return 0;

}/*
output:
ABDC ACBD ACDB ADBC ADCB BACD BADC BCAD
BCDA BDAC BDCA CABD CADB CBAD CBDA CDAB
CDBA DABC DACB DBAC DBCA DCAB DCBA ABCD*/

[JosAH]

You can also write line #7 like this:

char s[4]= "ABCD";
 

It does exactly the same but is a bit more convenient to write.

kind regards,

Jos

[whodgson]

Thanks Jos and Newb16....i get the idea.

[bwagner]

comment to JosAH's reply

You can also write line #7 like this ...

... or even more convenient (avoiding redundancy):

char s[]= "ABCD";