几天前，在我的笔记本电脑上运行的脚本与在另一个Linux机器上运行的脚本运行方式不同（我运行的脚本彼此相同）。我的猜测是我的编译器丢失了一些东西。我不知道问题是什么。
运行g ++ -v后，这是我得到的结果：
Apple LLVM version 7.0.0 (clang-700.1.76)
Target: x86_64-apple-darwin14.5.0
Thread model: posix
在这个其他Linux机器上运行g ++ -v后，我得到了：
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.8.3/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-linker-hash-style=gnu --enable-languages=c,c++,objc,obj-c++,java,fortran,ada,go,lto --enable-plugin --enable-initfini-array --disable-libgcj --with-isl=/builddir/build/BUILD/gcc-4.8.3-20140911/obj-x86_64-redhat-linux/isl-install --with-cloog=/builddir/build/BUILD/gcc-4.8.3-20140911/obj-x86_64-redhat-linux/cloog-install --enable-gnu-indirect-function --with-tune=generic --with-arch_32=x86-64 --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.8.3 20140911 (Red Hat 4.8.3-9) (GCC)
以下脚本是一个脚本，用于计算从一个源顶点到所有顶点的最短路径，在这种情况下它是顶点1.此脚本的输出列出每个顶点及其与源的最短距离。有问题的输入文件也列在下面。这是我的问题脚本：
#include <iostream>
#include <sstream>
#include <fstream>
#include <list>
#include <limits>
using namespace std;
struct Node{
int dist;
int v;
bool operator==(const Node& a){
return dist == a.dist;
}
bool operator!=(const Node& a){
return (!(dist == a.dist));
}
bool operator<(const Node& a){
return dist < a.dist;
}
bool operator>(const Node& a){
return a.dist < dist;
}
int operator+(const Node& a){
return a.dist+dist;
}
};
struct cheapHeap{
int curSize;
Node * minHeap;
};
class DijkstraSolution{
private:
int size;
int sourceV;
list<Node> *container; //this is the container to hold input data
int *results; //this is the array to hold final results
cheapHeap ch; //this is the array that holds each dist looked at
public:
DijkstraSolution(string fname, int inSourceV, int inSize): size(inSize), sourceV(inSourceV){
//read the file and initialize the list<Node> container
container = new list<Node>[size];
ifstream infile;
infile.open(fname.c_str());
string line = "";
if (infile){
while (getline(infile, line)){
istringstream iss(line);
int vertex;
int v;
int dist;
iss >> vertex;
while(iss >> v >> dist){
Node edges;
edges.dist = dist;
edges.v = v;
container[vertex].push_back(edges);
}
}
}
infile.close();
//initialization of results and minHeap array
int maxVal = numeric_limits<int>::max();
results = new int[size];
ch.curSize = size-1;
ch.minHeap = new Node[size];
for (int i = 0; i < size; i++){
results[i] = maxVal;
ch.minHeap[i].dist = maxVal;
}
results[sourceV] = 0;
ch.minHeap[sourceV].dist = 0;
ch.minHeap[sourceV].v = sourceV;
}
//find min of all nodes inserted into minHeap
Node findMin(){
Node minimum;
minimum.dist = numeric_limits<int>::max();
minimum.v = 0;
for (int i=1; i <= size; i++){
if ((ch.minHeap[i] < minimum) && (ch.minHeap[i].dist != -1)){
minimum = ch.minHeap[i];
}
}
ch.minHeap[minimum.v].dist = -1;
ch.curSize--;
return minimum;
}
//for every min that findMin() spits out, insert this min into the results array
int * dijkstra(){
while (ch.curSize != 0){
Node minimum = findMin();
results[minimum.v] = minimum.dist;
for (list<Node>::iterator it = container[minimum.v].begin(); it != container[minimum.v].end(); it++){
if ((*it)+minimum < ch.minHeap[(*it).v].dist){
Node inserted;
inserted.dist = *it + minimum;
inserted.v = (*it).v;
ch.minHeap[(*it).v] = inserted;
}
}
}
return results;
}
//this prints the contents from the file input
void printContainer(){
for (int i=1; i < size; i++){
cout << i << " ";
list<Node>::iterator iter;
for (iter = container[i].begin(); iter != container[i].end(); iter++){
cout << iter -> v << " " << iter -> dist << " ";
}
cout <<endl;
}
}
//this prints out the contents from the results array
void printResults(){
for (int i = 1; i < size; i++){
cout << i << " -> " << results[i] << endl;
}
}
};
int main(){
DijkstraSolution ds("pa5_test1.txt", 1, 9);
ds.dijkstra();
ds.printResults();
}
这是我的输入文件：
1 2 1 8 2
2 1 1 3 1
3 2 1 4 1
4 3 1 5 1
5 4 1 6 1
6 5 1 7 1
7 6 1 8 1
8 7 1 1 2
这是我从Mac上获得的输出，这是不正确的：
1 -> 0
2 -> 2147483647
3 -> 2147483647
4 -> 2147483647
5 -> 2147483647
6 -> 2147483647
7 -> 2147483647
8 -> 2147483647
这是我从其他Linux框中获得的输出，这是正确的：
1 -> 0
2 -> 1
3 -> 2
4 -> 3
5 -> 4
6 -> 4
7 -> 3
8 -> 2
显然，我的编译器没有更新结果数组。显然，它将第一个条目更新为0，然后它就会停止更新它。这真的很奇怪，因为我在不同的盒子上运行相同的代码，结果与Linux盒子相同，所以我猜它是我的编译器。令人沮丧的是我没有收到任何错误，所以我甚至不知道从哪里开始寻找答案。此外，不确定这是否相关，但是当我启动gdb时，它不会调试作为类编写的脚本。它只调试具有main和函数的代码，当我编写实例化某个类的main函数时它会跳闸。如果我的编译器确实坏了，有关如何重建它的任何建议（宝贝步骤）？对不起，很长的帖子。
答案 0 :(得分：2)
一个问题是：
for (int i=1; i <= size; i++){ // <-- Index goes out of bounds here
if ((ch.minHeap[i] < minimum) && (ch.minHeap[i].dist != -1)){
minimum = ch.minHeap[i];
您正在循环到size，但minHeap[size]是一个超出范围的访问权限。