CS1010E Programming Methodology

1. Tutorial 8 Question 1 CS1010EProgramming Methodology

2. Discussion • *variable (in declaration) means the variable is a pointer variable • *variable (in statement) refers to the value of the variable, NOT the address • NOTE: There is a missing information where the initial value of variable “i” is assigned as 0.

3. Discussion (cont’d) while (i < 5) { if (list[i] != i) { j = list[i]; swap(&list[i], &list[j]); printArray(list, 5); } else i++; }

4. Discussion (cont’d) void swap(int *x, int *y) { int temp; temp = *x; *x = *y; *y = temp; return; }

5. Discussion (cont’d) voidprintArray(int list[], int size) { for (i = 0; i < size; i++) { printf(“%d“, *list); list++; } printf(“\n”); return; }

6. Discussion (cont’d)

7. Discussion (cont’d) Answer (so far) : 1 2 4 3 0 2 1 4 3 0 4 1 2 3 0 0 1 2 3 4 Pattern printing…

8. Discussion (cont’d) voidprintPattern(int list[], int size) { inti; for (i = 1; i <= size; i++) printArray(list+(size-i), i); return; }

9. Discussion (cont’d) printArray(list+(size-i), i); list+(size-i)  refers to an address (array is a pointer where the address of each member is adjacent to the member next to it)

10. Discussion (cont’d) list[5] = {0, 1, 2, 3, 4}

11. Discussion (cont’d) Answer (final) : 1 2 4 3 0 2 1 4 3 0 4 1 2 3 0 0 1 2 3 4 Pattern printing… 4 3 4 2 3 4 1 2 3 4 0 1 2 3 4