Simple question about word reversing program

Code:

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#include <stdio.h>


int main()
{
        char s[40], gecici;
        int  i, n;
       
       
printf("write a word : ");
        scanf("%s",s);
       
        for(n=0; s[n] != '\0'; n++);
       
        for(i=0; i<n/2; i++){        /*I didn't understand why we                       

                                        have to put "n/2" as the       

                                                  condition */
                gecici  = s[n-i-1];
                s[n-i-1] = s[i];
                s[i]    = gecici;
        }
       
printf("reverse        : %s\n",s);
       
return0;
}

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this is not my code it works fine and everything I am just trying to understand the logic of the code. I have no idea why we put "n/2" as the condition. if I put "n-1" it still works too. I got everything else though.

Quote:

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Originally Posted by amadeus111

[CODE] if I put "n-1" it still works too.

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Input GeorgeSamarasDIT

You need n/2, because you have to go until the middle!

• you go along the word
• pick first letter and swap it with last letter
• Now the last is first and the first is last
• pick 2nd letter and swap it with prelast letter
• Now the prelast is second and the second is prelast
• ....

Think about it. Then scroll down.
.
.
.
.
..
.
.
.
You have to go until the middle of the word ;)

//welcome to the forum!

Thank you! It makes sense now! :) :)

You are welcome :D

Code:

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for(n=0; s[n] != '\0'; n++);

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Most people use a nice little routine called "strlen()" it results in much more readable code. When I first glanced at this code I said "this loop does absolutely nothing...". The highest priority when writing code is READABILITY.

You should practise more if you saw that with first glance.

Also, for a beginner it just ok to use it like this.

He probably haven't use string.h yet!