10/09/13 8:10
pistilloi
Come si può notare dalla sessione di debug sottopostata la variabile y assume il valore 4 pur essendo SIDE = 4 e specificato nel for y<SIDE. Come questa altre cose appaiono in memoria senza controllo...
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#define SIDE 4
#define true 1
#define false 0
typedef int Bool;
typedef struct Point { int x; int y; } Pnt;
typedef struct Letter{
char letter;
struct Letter * around[8];
Pnt position;
} Letter;
typedef Letter **Matrix;
/**
*
*
*/
Matrix matrix_new( int N, int M ) {
Matrix matrix;
int i;
matrix = (Matrix) malloc( N * sizeof(Letter*) ) ;
for (i=0; i<N; ++i)
matrix[i] = (Letter*) malloc( M * sizeof(Letter) )
;
return matrix ;
}
/**
*
*
*/
int distance_between_letters( Letter L1, Letter L2 ) {
Pnt p1 = L1.position ;
Pnt p2 = L2.position ;
return (int) sqrt(pow(p2.x-p1.x,2)+pow(p2.y-p1.y,2))
;
}
/**
*
*
*/
Letter around_of_letter( Matrix M, Letter L) {
int x,y;
int i=0;
for(x=0; x<SIDE; x++)
for(y=0; y<SIDE; y++) {
if( distance_between_letters( M[x][y], L ) == 1 )
L.around[i++] = &M[x][y]
;
else
L.around[i++] = NULL
;
// L.position.x = x ;
// L.position.y = y ;
}
return L ;
}
/**
*
*
*/
Matrix matrix_fill( Matrix M, char *W ) {
int x,y;
int i = 0;
for(x=0; x<SIDE; x++)
for(y=0; y<SIDE; y++) {
M[x][y].letter = W[i++];
M[x][y].position.x = x;
M[x][y].position.y = y;
}
for(x=0; x<SIDE; x++)
for(y=0; y<SIDE; y++)
M[x][y] = around_of_letter( M, M[x][y] )
;
return M ;
}
/**
*
*
*/
Bool search_on_matrix( Matrix M, Letter * L ) {
int x,y;
for(x=0; x<SIDE; x++)
for(y=0; y<SIDE; y++)
if( M[x][y].letter == L->letter ) {
L = &M[x][y] ;
return true ;
}
else
return false ;
}
/**
*
*
*/
Bool search_on_around( Letter * L, char C ) {
int i;
for(i=0; i<8; i++)
if( L->around[i] != NULL && L->around[i]->letter == C ) {
L = L->around[i] ;
return true ;
}
else
return false ;
}
/**
*
*
*/
Bool automatic_gamer( Matrix M, char *W ) {
int x,y;
int i = 0;
Letter L;
do {
switch(i) {
case 0:
L.letter = W[i];
if( !search_on_matrix( M, &L ) )
return false
;
break;
default:
if( !search_on_around( &L, W[i] ) )
return false
;
break;
}
} while( W[i++] != '
Come si può notare dalla sessione di debug sottopostata la variabile y assume il valore 4 pur essendo SIDE = 4 e specificato nel for y<SIDE. Come questa altre cose appaiono in memoria senza controllo...
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#define SIDE 4
#define true 1
#define false 0
typedef int Bool;
typedef struct Point { int x; int y; } Pnt;
typedef struct Letter{
char letter;
struct Letter * around[8];
Pnt position;
} Letter;
typedef Letter **Matrix;
/**
*
*
*/
Matrix matrix_new( int N, int M ) {
Matrix matrix;
int i;
matrix = (Matrix) malloc( N * sizeof(Letter*) ) ;
for (i=0; i<N; ++i)
matrix[i] = (Letter*) malloc( M * sizeof(Letter) )
;
return matrix ;
}
/**
*
*
*/
int distance_between_letters( Letter L1, Letter L2 ) {
Pnt p1 = L1.position ;
Pnt p2 = L2.position ;
return (int) sqrt(pow(p2.x-p1.x,2)+pow(p2.y-p1.y,2))
;
}
/**
*
*
*/
Letter around_of_letter( Matrix M, Letter L) {
int x,y;
int i=0;
for(x=0; x<SIDE; x++)
for(y=0; y<SIDE; y++) {
if( distance_between_letters( M[x][y], L ) == 1 )
L.around[i++] = &M[x][y]
;
else
L.around[i++] = NULL
;
// L.position.x = x ;
// L.position.y = y ;
}
return L ;
}
/**
*
*
*/
Matrix matrix_fill( Matrix M, char *W ) {
int x,y;
int i = 0;
for(x=0; x<SIDE; x++)
for(y=0; y<SIDE; y++) {
M[x][y].letter = W[i++];
M[x][y].position.x = x;
M[x][y].position.y = y;
}
for(x=0; x<SIDE; x++)
for(y=0; y<SIDE; y++)
M[x][y] = around_of_letter( M, M[x][y] )
;
return M ;
}
/**
*
*
*/
Bool search_on_matrix( Matrix M, Letter * L ) {
int x,y;
for(x=0; x<SIDE; x++)
for(y=0; y<SIDE; y++)
if( M[x][y].letter == L->letter ) {
L = &M[x][y] ;
return true ;
}
else
return false ;
}
/**
*
*
*/
Bool search_on_around( Letter * L, char C ) {
int i;
for(i=0; i<8; i++)
if( L->around[i] != NULL && L->around[i]->letter == C ) {
L = L->around[i] ;
return true ;
}
else
return false ;
}
/**
*
*
*/
Bool automatic_gamer( Matrix M, char *W ) {
int x,y;
int i = 0;
Letter L;
do {
switch(i) {
case 0:
L.letter = W[i];
if( !search_on_matrix( M, &L ) )
return false
;
break;
default:
if( !search_on_around( &L, W[i] ) )
return false
;
break;
}
} while( W[i++] != '{parsed_message}' ) ;
return true ;
}
void main() {
Matrix M = matrix_new(4,4);
M = matrix_fill( M, "ciaociaociaociao" ) ;
if(automatic_gamer(M,"ciao"))
printf("true!\n")
;
else printf("false!\n");
}
$ gdb a.out
(gdb) list around_of_letter
54
55 /**
56 *
57 *
58 */
59 Letter around_of_letter( Matrix M, Letter L) {
60
61 int x,y;
62 int i=0;
63
(gdb)
64 for(x=0; x<SIDE; x++)
65 for(y=0; y<SIDE; y++) {
66
67 if( distance_between_letters( M[x][y], L ) == 1 )
68 L.around[i++] = &M[x][y]
69 ;
70 else
71 L.around[i++] = NULL
72 ;
73
(gdb) break 64
Breakpoint 1 at 0x4007de: file prova.c, line 64.
(gdb) run
Starting program: /home/dante/Documenti/Ruzzle/0.3/a.out
Breakpoint 1, around_of_letter (M=0x603010, L=...) at prova.c:64
64 for(x=0; x<SIDE; x++)
(gdb) next
65 for(y=0; y<SIDE; y++) {
(gdb) next
67 if( distance_between_letters( M[x][y], L ) == 1 )
(gdb) print y
= 0
(gdb) next
71 L.around[i++] = NULL
(gdb) next
65 for(y=0; y<SIDE; y++) {
(gdb) next
67 if( distance_between_letters( M[x][y], L ) == 1 )
(gdb) print y
= 1
(gdb) next
68 L.around[i++] = &M[x][y]
(gdb) print y
= 1
(gdb) next
65 for(y=0; y<SIDE; y++) {
(gdb) next
67 if( distance_between_letters( M[x][y], L ) == 1 )
(gdb) next
71 L.around[i++] = NULL
(gdb) next
65 for(y=0; y<SIDE; y++) {
(gdb) next
67 if( distance_between_letters( M[x][y], L ) == 1 )
(gdb) next
71 L.around[i++] = NULL
(gdb) next
65 for(y=0; y<SIDE; y++) {
(gdb) next
64 for(x=0; x<SIDE; x++)
(gdb) print y
= 4
(gdb)
' ) ;
return true ;
}
void main() {
Matrix M = matrix_new(4,4);
M = matrix_fill( M, "ciaociaociaociao" ) ;
if(automatic_gamer(M,"ciao"))
printf("true!\n")
;
else printf("false!\n");
}
$ gdb a.out
(gdb) list around_of_letter
54
55 /**
56 *
57 *
58 */
59 Letter around_of_letter( Matrix M, Letter L) {
60
61 int x,y;
62 int i=0;
63
(gdb)
64 for(x=0; x<SIDE; x++)
65 for(y=0; y<SIDE; y++) {
66
67 if( distance_between_letters( M[x][y], L ) == 1 )
68 L.around[i++] = &M[x][y]
69 ;
70 else
71 L.around[i++] = NULL
72 ;
73
(gdb) break 64
Breakpoint 1 at 0x4007de: file prova.c, line 64.
(gdb) run
Starting program: /home/dante/Documenti/Ruzzle/0.3/a.out
Breakpoint 1, around_of_letter (M=0x603010, L=...) at prova.c:64
64 for(x=0; x<SIDE; x++)
(gdb) next
65 for(y=0; y<SIDE; y++) {
(gdb) next
67 if( distance_between_letters( M[x][y], L ) == 1 )
(gdb) print y
= 0
(gdb) next
71 L.around[i++] = NULL
(gdb) next
65 for(y=0; y<SIDE; y++) {
(gdb) next
67 if( distance_between_letters( M[x][y], L ) == 1 )
(gdb) print y
= 1
(gdb) next
68 L.around[i++] = &M[x][y]
(gdb) print y
= 1
(gdb) next
65 for(y=0; y<SIDE; y++) {
(gdb) next
67 if( distance_between_letters( M[x][y], L ) == 1 )
(gdb) next
71 L.around[i++] = NULL
(gdb) next
65 for(y=0; y<SIDE; y++) {
(gdb) next
67 if( distance_between_letters( M[x][y], L ) == 1 )
(gdb) next
71 L.around[i++] = NULL
(gdb) next
65 for(y=0; y<SIDE; y++) {
(gdb) next
64 for(x=0; x<SIDE; x++)
(gdb) print y
= 4
(gdb)
aaa
