String Reversal without using indexing.

Jaks_maths 0 136 Views

Used recursion to reverse the string. Another method for string reversal.

#include<stdio.h>
#include<string.h>
char *strrev(char *str)
{
char s[2],*t;
if(strlen(str)==1)
return &str[0];
else
{
s[0]=str[0];
s[1]='\0';
t=strrev((str+1));
strcat(t,s);
return t;
}
}
main()
{
char *str,*dstr;
printf("\n Enter Input string ");
gets(str);
dstr="";
dstr=strrev(str);
printf(" Reverse String %s",dstr);
}
Member Avatar for ~s.o.s~
~s.o.s~ 2,560 Failure as a human

The above method for gettign the string from the user wont work and would give an run time error since the user input is stored in a character ptr for whom no memory has been allocated.

Better use

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

char *strrev(char *str)
{
  char s[2],*t;
  if(strlen(str)==1)
    return &str[0];
  else
  {
    s[0]=str[0];
    s[1]='[B]\0[/B]';
    t=strrev((str+1));
    strcat(t,s);
    return t;
   }
}


int main (void)
{
  char str[BUFSIZ];
  char* dstr;
  printf("[B]\n[/B] Enter Input string ");
  fgets(str, BUFSIZ, stdin);
  dstr="";
  dstr=strrev(str);
  printf(" Reverse String %s",dstr);
}
Member Avatar for risby
risby 0 Newbie Poster

Untested, unformatted, uses deprecated functions like gets and doesn't allocate space for its data. Should be removed.

Member Avatar for ~s.o.s~
~s.o.s~ 2,560 Failure as a human

Thats the reason i posted the updated version which works and uses safe functions like fgets().
:mrgreen:

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