01  #include<stdio.h>
02  #include<string.h>
03  
04  int main()
05  {
06   
07   char str[20] = "HELLO WORLD";
08   printf("Original string is: %sn", str);
09   strlwr(str);
10   printf("String after strlwr: %sn", str);
11   
12   return 0;
13  }

 
 OUTPUT :
 
 Original string is: HELLO WORLD
 
 String after strlwr: hello world