Possible Duplicates:
C: differences between pointer and array
Different sizeof results

Basically, I did this...

 char *str1 = "Sanjeev";
 char str2[] = "Sanjeev";
 printf("%d %d\n",strlen(str1),sizeof(str1));    
 printf("%d %d\n",strlen(str2),sizeof(str2));

and my output was

7 4
7 8

I'm not able to give reasons as to why the sizeof str1 is 4. Please explain the difference between these.