Write a C Program To Write function to upper the string

Write a C Program To Write function to Reverse the string

1:  #include<stdio.h>  
2:  #include<conio.h>  
3:  void reverse(char[]);  
4:  int main()  
5:  {  
6:        char str[20];  
7:        clrscr();  
8:        printf("Enter string : ");  
9:        gets(str);  
10:        reverse(str);  
11:        getch();  
12:        return 0;  
13:  }  
14:  void reverse(char str[20])  
15:  {  
16:        int i;  
17:        printf("%s in reverse order is ",str);  
18:        for(i=strlen(str)-1;i>=0;i--)  
19:              printf("%c",str[i]);  
20:  }