Here, I have a bad program. Its outputs confusing me, anyone can tell me why ? #include <stdio.h> #include <stdlib.h> int main() { int i = 0; char *a_result[10]; char *b_result[10]; for (i = 0; i < 10; i++) { char a_array[10]; char *b_array = malloc(10*sizeof(char)); int j = 0; for (j = 0; j < 9; j++) { a_array[j] = 'a' + i; b_array[j] = 'a' + i; } a_array[j] = '\0'; b_array[j] = '\0'; a_result[i] = a_array; b_result[i] = b_array; } for (i = 0; i < 10; i++) printf("a_result: %s b_result: %s\n",a_result[i],b_result[i]); return 0; } I think the a_result and b_result should be the same, but it is not. Here is the output on my computer. a_result: jjjjjjjjj b_result: aaaaaaaaa a_result: jjjjjjjjj b_result: bbbbbbbbb a_result: jjjjjjjjj b_result: ccccccccc a_result: jjjjjjjjj b_result: ddddddddd a_result: jjjjjjjjj b_result: eeeeeeeee a_result: jjjjjjjjj b_result: fffffffff a_result: jjjjjjjjj b_result: ggggggggg a_result: jjjjjjjjj b_result: hhhhhhhhh a_result: jjjjjjjjj b_result: iiiiiiiii a_result: jjjjjjjjj b_result: jjjjjjjjj any explanation about this is appreciate!