Lösung:
1 #include <iostream >
2 using namespace std;
3
4 //#define DEBUG
5
6 int main (){
7 const unsigned int n = 5;
8 unsigned int matrix[n][n];
9
10 unsigned int k=0; /* auxilary variable */
11 unsigned int i=0; /* element counter */
12 unsigned int r=0; /* rows <> */
13 int c=-1; /* columnes ˆv */
14 while(i < n*n){
15 /* direction: right */
16 for(unsigned int j=0; j<n-k; j++){
17 i++; /* increment element value */
18 matrix[r][++c] =i; /* write element value */
19 #ifdef DEBUG
20 cout <<" >" <<r <<"," <<c <<"="<<i;
21 #endif
22 }
23 #ifdef DEBUG
24 cout <<endl;
25 #endif
26
27 /* direction: down */
28 if(i < n*n){
29 k++;
30 for(unsigned int j=0; j<n-k; j++){
31 i++; /* increment element value */
32 matrix [++r][c] = i; /* write element value */
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5 / 5 INFO1: ¨Ubung Nr. 3
33 #ifdef DEBUG
34 cout <<" v" <<r <<"," <<c <<"="<<i;
35 #endif
36 }
37 #ifdef DEBUG
38 cout <<endl;
39 #endif
40 }
41
42 /* direction: left */
43 if(i < n*n){
44 for(unsigned int j=0; j<n-k; j++){
45 i++; /* increment element value */
46 matrix[r][--c] = i; /* write element value */
47 #ifdef DEBUG
48 cout <<" <" <<r <<"," <<c <<"="<<i;
49 #endif
50 }
51 #ifdef DEBUG
52 cout <<endl;
53 #endif
54 }
55
56 /* direction: up */
57 if(i < n*n){
58 k++;
59 for(unsigned int j=0; j<n-k; j++){
60 i++; /* increment element value */
61 matrix[--r][c] = i; /* write element value */
62 #ifdef DEBUG
63 cout <<" ˆ" <<r <<"," <<c <<"="<<i;
64 #endif
65 }
66 #ifdef DEBUG
67 cout <<endl;
68 #endif
69 }
70 }
71
72 for(unsigned int r = 0; r < n; ++r){
73 for(unsigned int c = 0; c < n; ++c){
74 if(matrix[r][c] < 10){
75 cout << ’ ’;
76 }
77 cout << matrix[r][c] << ’ ’;
78 }
79 cout << endl;
80 }
81 return 0;
82 }