my_strrev(char str[Max]){
    int i; // pointing to base adress
    int l; //pointing to last address strlen(str) -1th position
    char temp;
    for(i=0,l=strlen(str)-1;i<=l; i++ ,j--)
    {
      temp=str[i];
      str[i]=str[l];
      str[l]=temp;
    }
    return str;
}

char * rev(char * str){
 int temp;  
 for(int j=0;str[j];j++);     
 for(int i=0;i<j;i++,j--){
        temp=str[i];
        str[i]=str[j];
        str[j]=temp;
    } 
 return str;
}

#include<iostream.h>
#include<conio.h>
#include<string.h>
#include<stdio.h>
int main()
{
int i=0,l,l1;
char str[100];
cout<<"enter string:";
gets(str);
while(str[i])
i++;
l=i;
for(i=0;i<=(l-1)/2;i++)   //n/2 steps!!no extra memory
{
char t=str[i];
str[i]=str[l-i-1];
str[l-i-1]=t;
}
str[l]=0;
cout<<"\n\nreversed string is:"<<str;
getch();
return 0;
}

char * rev_string (char * str)
{
char temp;
int i , j;
for (i = 0 ; str[i]!= NULL ; i++);

for(j = 0 ; j < i ; j++ , i--)
{
      temp = str[j];
      str[j] = str[i];
      str[i] = temp;
}

return str;
}

the above is slightly wrong
this is the corrected one..

char * rev_string (char * str)
{
char temp;
int i , j;
for (i = 0 ; str[i]!= '\0' ; i++);

for(j = 0 ; j < i ; j++ , i--)
{
      temp = str[j];
      str[j] = str[i];
      str[i] = temp;
}

return str;
}

#include<stdio.h>

void reverse(char *);

void main()
{
	char str[]="Hello";

	reverse(str);
	printf("Reverse String is %s",str);
	
}

void reverse(char *p)
{

	char *q=p;
	while(*++q!='\0');
	q--;

	while(p<q)
	{
		*p=*p+*q;
		*q=*p-*q;
		*p=*p-*q;
		p++;
		q--;
	}

}

char * rev_string (char * str)
{
char temp;
int i , j;
for (i = 0 ; str[i]!= '\0' ; i++);
i--;

for(j = 0 ; j < i ; j++ , i--)
{
      temp = str[j];
      str[j] = str[i];
      str[i] = temp;
}

return str;
}

#include<muthu.h>
main()
 {
   printf("\nthe reverse string is:",reversemuthu(s1);
 }

output:
 original string is: muthu
 the reverse string is: uthum
   
Thanks and recgards:
   prof.muthu ph:9962940220
 you can call me any time any where...!

all these methods are too long.....


HAVE A LOOK ON SIMPLEST AND THE SHORTEST OF ALL 
IN JUST ONE LINE YOU CAN REVERSE ANY STRING
and yes..... without using string.h

CODE IS :



#include<stdio.h>
main()
{
int l,i,j;     /*declaring integer variables*/
char str[10],temp[10];   /* declaring string variables*/

/* Now taking input from the user*/

printf("\n enter any string to reverse =>");
scanf("%s",&str); /* passing into the variable*/

/*finding the lenth of the entered string */
for (l=0;str[l];++l); /*length found;amazing code!isnt it?*/
{printf("\nThis is the length of the string =>%d\n",l);}

/*making loop for reversing the given string*/

j=l;
for (i=0;j>=0;i++,j--)
{
temp[i]=str[j];    /* Note that the string is reversed */
                   /* and saved into new variable i.e temp*/
}

/*Now printing the reversed string*/
printf("\n this is the reversed string =>");

for (i=0;i<=l;i++)
{printf("%c",temp[i]);

/* this loop is calling the characters from the temp variable*/
}
}
/*End of program :-D*/




So this was my coding .....
am abhishek joshi.....
computer and network engineer....
am dot net programmer but also have indepth knowledge of C
and C++
and if you feel this code helpful then at least mention one
thanks vote on my mail id : h7_2007@yahoo.co.in

also if you want such amazing codes of dot net then u can
contact me.....
+919907428052
:-D have a great day.....

int i=0,j=0;
while(str[i++))
{j++;}
i=0;
j--;
while(i<j)
{ char tmp;
  tmp = str[i];
  str[i]=str[j];
  str[j]=tmp;
}

#include<stdio.h>
int main()
{
  char str[80],str1[80];
  int i,j;
 printf("\n Enter String:");
 fgets(str,80,stdin);
  for(i=strlen(str)-1,j=0;i>=1;i--)
      str1[j++]=str[i];
 printf("Reversed String is:%s",str1);
}

/*The program to reverse the given input string*/

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

void main()
{
   char str[20];
   int i=0,a,b;
   clrscr();

   printf("\nEnter the given string:");
   scanf("%s",str);

   do
   {
	 a=str[i];
	 i++;
   }while(a!=0);

   i=i-1;
   printf("\nThe reverse string:");

   do
   {
	 b=str[i];
	 printf("%c",b);
	 i--;
   }while(i>=0);

   getch();

int l=0,i;
while(str[l]!='\0')
{
l++;
}
for(i=l-1;i>=0;i--)
{
cout<<str{i];
}