我正在撰寫一個程式，我試圖在其中使用鄰接串列構建圖形資料結構。圖結構中的頂點有一個 ID、x 和 y 坐標，以及一個關聯的鄰接串列，其中包含有關子頂點是什么以及到達它們所花費的權重的資訊。
我曾嘗試使用列印陳述句進行除錯，例如 Graph 類中的 for 回圈，但我無法列印有關已push_back編輯到名為 graph 的向量中的頂點的任何資訊。此外，我知道坐標檔案的所有內容都已讀入，但每當我嘗試從邊緣檔案創建鄰接串列時，我都會收到一個Segmentation fault (core dumped). 我試圖在 Visual Studio Code 上使用除錯器，但它說程式能夠運行而沒有任何錯誤，盡管我在編譯后遇到了分段錯誤。
我怎樣才能停止得到這個分段錯誤？我也嘗試過調整陣列的大小，但這也不起作用。我在嘗試創建的 for 回圈中遇到了分段錯誤。我不確定為什么沒有將頂點物件添加到我創建的向量中。有人可以指導我如何實際添加它們嗎？
#ifndef VERTEX_H
#define VERTEX_H
#include <vector>
#define INF 1000000000
using namespace std;
class Vertex {
public:
int id;
Vertex* parent;
bool visited; // Flag to see if this vertex has been visited
vector<pair<Vertex*, int>> children; // Connecting vertices to this vertex
float g; // Path cost from source vertex to this vertex
float h; // Heuristic ost from this node to goal node
int x; // x-coordinate of vertex in graph space
int y; // y-coordinate of vertex in graph space
// Constructor
Vertex(int id, int x, int y) {
this->id = id;
this->x = x;
this->y = y;
this->g = INF;
this->h = INF;
parent = NULL;
visited = false;
}
// Add an edge to the vertex, populate the adjacency list
void addEdge(Vertex* child, int weight) {
children.push_back(make_pair(child, weight));
}
// Generic heuristic value calculation
float f() {
return g h;
}
};
#endif
#ifndef GRAPH_H
#define GRAPH_H
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
#include <sstream>
#include <vector>
using std::ifstream;
#include "Vertex.h"
using namespace std;
class Graph {
public:
vector<Vertex*> graph;
int vertexCount;
string edges;
string coordinates;
// Constructor
Graph(string edges, string coordinates, int vertexCount) {
this->edges = edges;
this->coordinates = coordinates;
this->vertexCount = vertexCount;
this->graph = createGraph(edges, coordinates, vertexCount);
};
vector<Vertex*> createGraph(string edges, string coordinates, int vertexCount) {
vector<Vertex*> graph;
// Read in coordinate information of vertices
ifstream coordinateInput(coordinates);
string line1, tempString1, tempString2, tempString3;
int vertex; // Member ID of the vertex
float x, y;
while (getline(coordinateInput, line1)) {
stringstream ss(line1);
getline(ss, tempString1, ',');
if (tempString1 == "--------------") break;
vertex = stoi(tempString1);
if (vertex >= graph.size()) {
graph.resize(vertex 1); // Resize
}
getline(ss, tempString2, ',');
x = stof(tempString2);
getline(ss, tempString3, ',');
y = stof(tempString3);
graph.push_back(new Vertex(vertex, x, y));
}
coordinateInput.close();
for (Vertex* v : graph) {
std::cout << "here" << endl;
std::cout << v->id << ' ' << v->x << v->y << endl;
}
std::cout << "Finished" << endl;
// Read in edge information and add them to the graph
ifstream edgeInput(edges);
int src, dest, weight;
string line2, tempString4, tempString5, tempString6;
while (getline(edgeInput, line2)) {
stringstream ss(line2);
getline(ss, tempString4, ',');
if (tempString4 == "--------------") break;
src = stoi(tempString4);
getline(ss, tempString5, ',');
dest = stoi(tempString5);
getline(ss, tempString6, ',');
weight = stoi(tempString6);
std::cout << graph[src]->id << endl;
std::cout << src << ' ' << dest << ' ' << weight << endl;
graph[src]->addEdge(graph[dest], weight);
}
edgeInput.close();
return graph;
}
};
#endif
我正在嘗試讀取的資料：坐標：
1,42.66,73.78
2,33.76,84.40
3,30.30,97.75
4,42.32,71.09
5,42.90,78.85
6,51.00,114.00
7,35.21,80.83
8,41.84,87.68
9,41.48,81.67
10,32.80,96.79
11,39.73,104.97
12,41.59,93.62
13,31.79,106.42
14,48.87,-2.33
15,32.74,97.33
16,29.76,95.38
17,39.79,86.15
18,30.32,81.66
19,35.68,220.23
20,39.08,94.56
21,24.56,81.78
22,30.19,82.64
23,36.19,115.22
24,34.03,118.17
25,42.33,122.86
26,35.12,89.97
27,25.79,80.22
28,44.96,93.27
29,37.3,120.9
30,45.50,73.67
31,29.97,90.06
32,40.70,73.92
33,28.53,81.38
34,40.72,76.12
35,33.53,112.08
36,38.07,122.81
37,45.52,122.64
38,35.82,78.64
39,39.53,119.82
40,38.56,121.47
41,29.45,98.51
42,37.76,122.44
43,37.30,121.87
44,46.49,84.35
45,47.63,122.33
46,37.69,97.34
47,39.76,84.20
48,35.27,120.66
49,27.97,82.46
50,30.45,84.27
51,43.65,79.38
52,38.91,77.01
53,40.75,111.89
--------------
邊緣：
1,30,226
1,2,1003
1,32,153
1,4,166
1,5,212
2,4,1075
2,26,456
2,50,308
3,16,186
3,13,577
3,15,190
3,41,79
3,31,511
4,5,455
4,32,215
4,30,161
4,28,1391
5,51,105
5,9,191
6,52,605
6,32,829
6,51,2116
7,18,432
7,38,165
7,8,987
8,28,511
8,46,361
9,34,476
9,47,214
9,51,292
9,10,1341
10,11,792
10,15,20
10,16,248
10,41,374
11,46,523
11,35,466
11,35,386
12,44,135
12,28,246
12,4,933
12,26,789
12,50,310
12,13,1132
13,41,580
13,35,320
13,35,328
14,34,3939
14,19,5313
15,44,314
15,17,413
16,15,101
16,31,321
17,18,1014
17,20,502
17,50,432
18,33,146
18,22,113
19,36,5131
19,48,5451
20,44,249
20,46,190
20,21,1092
20,22,1231
21,49,446
21,22,2341
21,29,892
22,27,902
22,49,169
22,50,104
22,23,421
23,24,275
23,53,486
23,39,439
24,43,124
24,48,182
24,29,328
25,37,275
25,36,365
26,44,413
27,33,235
27,49,282
27,21,159
28,32,463
28,25,1920
29,40,80
30,51,401
30,29,1080
31,50,388
31,32,1901
32,34,101
32,53,1311
32,24,1531
33,49,84
33,32,1343
34,14,3548
34,52,147
35,43,518
36,37,642
36,24,962
36,42,635
36,40,115
36,48,271
37,45,174
37,53,777
38,52,371
39,53,520
39,40,133
40,41,140
40,42,95
41,48,895
41,42,2093
42,43,50
42,48,232
43,48,168
44,32,882
44,51,436
45,52,115
46,53,335
47,17,165
47,46,795
47,9,212
48,51,2751
48,50,133
48,52,232
51,18,486
52,51,2095
49,50,275
49,51,1335
49,53,2328
50,11,795
50,52,2095
51,15,201
51,16,248
52,41,373
52,19,4869
53,52,2084
53,26,1243
53,51,2343
36,43,519
15,32,643
46,24,962
46,42,633
38,40,113
26,48,222
16,19,3431
27,40,123
35,43,1131
25,45,220
15,11,341
25,42,1232
--------------
uj5u.com熱心網友回復：
這是一個帶有嵌入式資料的精簡版本，演示了我如何解決這個問題。由于嵌入的資料集，我不得不進行一些修改，但您應該能夠很容易地調整它以從檔案中讀取。畢竟，溪流就是蒸汽。
課堂上你應該注意的一項修改Vertex：
int x; // x-coordinate of vertex in graph space
int y; // y-coordinate of vertex in graph space
Vertex(int id, int x, int y) {
我將成員型別和建構式引數更改為float. 資料被決議為浮點數，但在傳遞給建構式時被截斷。如果您打算這樣做，那很好，但對我來說似乎很奇怪。
你決議資料的方式沒有什么特別的問題，我只是改變了它來展示一個替代方案。您應該意識到這一點，如果無法決議資料stoi，則會引發例外。stof您也不需要檔案中的最后一行，if (tempString4 == "--------------") break;因為std::getline當它到達末尾時會失敗并中斷回圈。
#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#define INF 1000000000
using namespace std;
class Vertex {
public:
int id;
vector<pair<Vertex*, int>> children; // Connecting vertices to this vertex
float x; // x-coordinate of vertex in graph space
float y; // y-coordinate of vertex in graph space
Vertex(int id, float x, float y) {
this->id = id;
this->x = x;
this->y = y;
}
void addEdge(Vertex* child, int weight) {
children.push_back(make_pair(child, weight));
}
};
class Graph {
public:
vector<Vertex*> graph;
int vertexCount;
Graph(std::istream& edges, std::istream& coordinates) {
graph = createGraph(edges, coordinates);
vertexCount = static_cast<int>(graph.size()) - 1;
};
~Graph()
{
for (auto& v : graph)
{
delete v;
}
}
vector<Vertex*> createGraph(std::istream& edges, std::istream& coordinates) {
vector<Vertex*> ret(1);
string line;
while (getline(coordinates, line)) {
stringstream ss(line);
int vertex;
float x;
float y;
char comma;
if (ss >> vertex >> comma >> x >> comma >> y && ss.eof())
{
ret.push_back(new Vertex(vertex, x, y));
}
else
{
std::cout << "Data error parsing vertex from '" << line << "'\n";
}
}
for (Vertex* v : ret) {
if (v)
{
std::cout << v->id << ' ' << v->x << ", " << v->y << endl;
}
}
while (getline(edges, line)) {
stringstream ss(line);
int src;
int dest;
int weight;
char comma;
if (ss >> src >> comma >> dest >> comma >> weight && ss.eof())
{
if (src < static_cast<int>(ret.size()) && ret[src])
{
//hack to force dest into range 1, 10 of limited dataset
dest = 1 dest % 10;
ret[src]->addEdge(ret[dest], weight);
}
else
{
std::cout << "Data error: src " << src << " invalid\n";
}
}
else
{
std::cout << "Data error parsing edge from '" << line << "'\n";
}
}
return ret;
}
};
int main()
{
std::istringstream coordinates(
"1, 42.66, 73.78\n"
"2, 33.76, 84.40\n"
"3, 30.30, 97.75\n"
"4, 42.32, 71.09\n"
"5, 42.90, 78.85\n"
"6, 51.00, 114.00\n"
"7, 35.21, 80.83\n"
"8, 41.84, 87.68\n"
"9, 41.48, 81.67\n"
"10, 32.80, 96.79");
std::istringstream edges(
"1, 20, 226\n1, 2, 1003\n1, 32, 153\n1, 4, 166\n1, 5, 212\n"
"2, 4, 1075\n2, 26, 456\n2, 50, 308\n"
"3, 16, 186\n3, 13, 577\n3, 15, 190\n3, 41, 79\n3, 31, 511\n"
"4, 5, 455\n4, 32, 215\n4, 30, 161\n4, 28, 1391\n"
"5, 51, 105\n5, 9, 191\n"
"6, 52, 605\n6, 32, 829\n6, 51, 2116\n7, 18, 432\n7, 38, 165\n7, 8, 987\n"
"8, 28, 511\n8, 46, 361\n"
"9, 34, 476\n9, 47, 214\n9, 51, 292\n9, 10, 1341\n"
"10, 11, 792\n10, 15, 20\n10, 16, 248\n10, 41, 374"
);
Graph g(edges, coordinates);
for (const auto& v : g.graph)
{
if (v)
{
std::cout << "\n";
std::cout << v->id << ", " << v->x << ", " << v->y << "\n";
for (const auto& e : v->children)
{
std::cout << "\t";
std::cout << e.first->id << ", " << e.first->x << ", " << e.first->y << ", " << e.second << "\n";
}
}
}
}
Godbolt 示例
轉載請註明出處，本文鏈接：https://www.uj5u.com/caozuo/446203.html