itoa using reverse(string) code showing error

Question

Why doesn't ANSI C use strrev instead of creating such a big reverse function?

This code is showing me an error. Please correct it. What is the error. I am using Code::Blocks

Error message that I get:

c:\programfiles(x86)\codeblocks\mingw\bin..\lib\gcc\mingw32\4.7.1......\libmingw32.a(main.o):main.c:(.text.startup+0xa7)||undefined reference to `WinMain@16'|

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

 void reverse(int n, char s[])
 {
     int c,i, j;

     for(i=0, j= strlen(s)-1; i<j; i++, j--){
         c=s[i];
         s[i]=s[j];
         s[j]=c;
     }
  }

 void itoa(int n, char s[])
 {
     int i=0 ,sign;

     if((sign=n) < 0 )
         n= -n;
     do{
         s[i++] = n%10 + '0';
     }while(n /=10 >0);

     if(sign <0)
         s[i++] = '-';

     s[i] = '\0';
     reverse(n, s);
 }

Answer 1

Your code has no entry point. You need to have a main function, or WinMain or something.

http://mingw-starter.blogspot.com/2008/02/mingw-sdl.html says

Also, don't forget to add the -mwindows flag, if your IDE doesn't add it automatically (in addition to whatever other libraries you want to link). If you don't put them in the right order, you'll get a linker error complaining about the missing symbol WinMain@16.