Change string to lower case without strlwr in C

#include<stdio.h>
 
void lower_string(char*);
 
main()
{
   char string[100];
 
   printf("Enter a string to convert it into lower case\n");
   gets(string);
 
   lower_string(string);
 
   printf("Entered string in lower case is \"%s\"\n", string);
 
   return 0;
}
 
void lower_string(char *string)
{
   while(*string)
   {
      if ( *string >= 'A' && *string <= 'Z' )
      {
         *string = *string + 32;
      }
      string++;
   }
}