Thread: reverse a word

hello all,

please help me to understand the following code; it compile fine but the it gives the correct result only for a word of length =< 3. However if I comment out the statement printf("len = %d\n",len) it works fine for all inputs.

Code:

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

char *ptr;


  
int main(int args, char *argv[]){
       
 int len = strlen(argv[1]);
 //printf("len = %d\n",len);
 int j = len - 1, i;
 char ch[len];
         for( ptr=argv[1],i=0; i<len; i++,j--){         
                 
              ch[i]=*(ptr + j); 
              }
                          
                 printf(ch);
                 printf("\n");
             
      system("PAUSE"); 
      }