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コードを編集し、valgrindを使ってデバッグした結果を追加しました

2020/04/26 10:58

投稿

aardvark

スコア17

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test CHANGED Viewed

@@ -345,3 +345,453 @@
 }コード
 ```
+編集:皆様、ありがとうございます。
+コードを以下のように編集し、valgrindをランしてみたところ、以下のようなメッセージが出ました。
+こちらはどのように解釈されるのでしょうか？
+```C
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#define NEW(p, n){p = malloc((n)*sizeof(p[0]));}
+typedef struct slobj_{
+    struct slobj_* next;
+    int j;
+    double v;
+}* slobj;
+typedef struct{
+    slobj head;
+    slobj tail;
+}* slist;
+typedef struct{
+    int n,m;
+    slist* A;
+} smatrix;
+slist slist_new(void){
+    slist L;
+    NEW(L, 1);
+    L -> head = NULL;
+    L -> tail = NULL;
+    return L;
+}
+slobj slobj_new(int x, double y){
+    slobj p;
+    NEW(p, 1);
+    p -> j = x;
+    p -> v = y;
+    p -> next = NULL;
+    return p;
+}
+void slist_insert_head(slist L, slobj p){
+    p -> next = L -> head;
+    L -> head = p;
+}
+void slist_insert_tail(slist L, slobj p){
+    if(L -> head == NULL){
+        L -> tail = p;
+        L -> head = p;
+    }
+    else if(L -> head == L -> tail){
+        L -> tail = p;
+        L -> head -> next = p;
+    }
+    else{
+        L -> tail -> next = p;
+        L -> tail = p;
+    }
+}
+void slist_print(slist L)
+{
+    slobj p;
+    p = L->head;
+    while (p != NULL){
+        printf("%d ", p -> j);
+        printf("%lf ", p -> v);
+        p = p-> next;
+    }
+}
+smatrix smatrix_new(int n, int m){
+    smatrix S;
+    int i;
+    NEW(S.A, n);
+    S.n = n;
+    S.m = m;
+    for(i=0; i<= n-1; i++){
+        S.A[i]=slist_new();
+    }
+    return S;
+}
+smatrix smatrix_read(void){
+    smatrix S;
+    slobj p;
+    int i, n, m, j;
+    double v;
+    scanf("%d", &n);
+    scanf("%d", &m);
+    S = smatrix_new(n, m);
+    for(i = 0; i <= n-1; i++){
+        while(1){
+            scanf("%d", &j);
+            if (j < 0){
+                break;
+            }
+            scanf("%lf", &v);
+            slobj p = slobj_new(j, v);
+            slist_insert_tail(S.A[i], p);
+        }
+    }
+    return S;
+}
+void smatrix_print(smatrix S){
+    int i;
+    printf("%d ", S.n);
+    printf("%d\n", S.m);
+    for(i = 0; i <= S.n-1; i++){
+        slist_print(S.A[i]);
+        printf("%d\n", -1);
+    }
+}
+smatrix smatrix_transpose(smatrix S){
+    int i, k;
+    double x;
+    slobj p, q;
+    smatrix T;
+    for(i = 0; i <= S.n-1; i++){
+        p = S.A[i]->head;
+        while(1){
+           k = p->j;
+           x = p->v;
+           q = slobj_new(i+1, x);
+           slist_insert_tail(T.A[k-1], q);
+           p = p->next;
+           if(p=NULL){
+               break;
+           }
+        }
+    }
+    return T;
+}
+void slist_free(slist L)
+{
+    slobj p, q, r;
+    p = L->head;
+    q = p->next;
+    while (q != NULL){
+        r = q;
+        q = q-> next;
+        free(p);
+        p = r;
+    }
+    free(L);
+}
+void smatrix_free(smatrix S){
+    int i;
+    for(i = 0; i <= S.n-1; i++){
+        if(S.A[i]->head != NULL){
+            slist_free(S.A[i]);
+        }
+    }
+}
+int main(){
+    smatrix A;
+    smatrix B;
+    A = smatrix_read();
+    smatrix_print(A);
+    B = smatrix_transpose(A);
+    smatrix_print(B);
+    smatrix_free(A);
+    smatrix_free(B);
+    return 0;
+}
+```
+```valgrind
+==1188== Memcheck, a memory error detector
+==1188== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
+==1188== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
+==1188== Command: ./a.out
+==1188==
+==1188== error calling PR_SET_PTRACER, vgdb might block
+2 3
+1 1.0 -1
+2 3.4 -1
+2 3
+1 1.000000 -1
+2 3.400000 -1
+==1188== Use of uninitialised value of size 8
+==1188==    at 0x108BD3: smatrix_transpose (in /home/keigoh/a.out)
+==1188==    by 0x108D26: main (in /home/keigoh/a.out)
+==1188==
+==1188== Invalid read of size 8
+==1188==    at 0x108BD3: smatrix_transpose (in /home/keigoh/a.out)
+==1188==    by 0x108D26: main (in /home/keigoh/a.out)
+==1188==  Address 0x2b911eb00 is not stack'd, malloc'd or (recently) free'd
+==1188==
+==1188==
+==1188== Process terminating with default action of signal 11 (SIGSEGV)
+==1188==  Access not within mapped region at address 0x2B911EB00
+==1188==    at 0x108BD3: smatrix_transpose (in /home/keigoh/a.out)
+==1188==    by 0x108D26: main (in /home/keigoh/a.out)
+==1188==  If you believe this happened as a result of a stack
+==1188==  overflow in your program's main thread (unlikely but
+==1188==  possible), you can try to increase the size of the
+==1188==  main thread stack using the --main-stacksize= flag.
+==1188==  The main thread stack size used in this run was 8388608.
+==1188==
+==1188== HEAP SUMMARY:
+==1188==     in use at exit: 120 bytes in 6 blocks
+==1188==   total heap usage: 8 allocs, 2 frees, 2,168 bytes allocated
+==1188==
+==1188== LEAK SUMMARY:
+==1188==    definitely lost: 0 bytes in 0 blocks
+==1188==    indirectly lost: 0 bytes in 0 blocks
+==1188==      possibly lost: 0 bytes in 0 blocks
+==1188==    still reachable: 120 bytes in 6 blocks
+==1188==         suppressed: 0 bytes in 0 blocks
+==1188== Rerun with --leak-check=full to see details of leaked memory
+==1188==
+==1188== For counts of detected and suppressed errors, rerun with: -v
+==1188== Use --track-origins=yes to see where uninitialised values come from
+==1188== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
+Segmentation fault (core dumped)
+```