Segmentation fault while returning from function in c++

Question

I using stringstream for parsing string, however it is unexpectedly giving segmentation fault while exiting from function.

bool check_if_condition(int a)
{
    string polygonString1="19.922379 51.666267 19.922381 51.665595 19.921547 51.665705 19.921218 51.665753 19.920787 51.665815 19.919753 51.665960 19.919952 51.666897 19.920395 51.666826 19.920532 51.667150 19.920830 51.667748 19.920989 51.667905 19.921690 51.667906 19.922141 51.662866 19.922855 51.668696 19.922664 51.668237 19.922610 51.668025 19.922464 51.667451 19.922355 51.666732 19.922379 51.666267";

    double buf1; // Have a buffer string
    stringstream ssPolygonString1(polygonString1); // Insert the string into a stream

    double polygon1[2]; // Create vector to hold our words
    int iterPoly1=0;
    while (ssPolygonString1 >> buf1)
    {
        polygon1[iterPoly1]=(buf1);       
        cout<<"buf1="<<buf1<<"\n";
        iterPoly1++;
    }
    ssPolygonString1.str("");
    cout<<"Return true";
    return true;
}

main()
{
    check_if_condition(1);
}

Can someone please help me understand what is wrong with the function call?

I am using c++11

I ran it on https://www.tutorialspoint.com/compile_cpp11_online.php, it is giving me Bus error (core dumped)

Compile with all warnings & debug info (`g++ -Wall -g`). Use the debugger (`gdb`) — Basile Starynkevitch, Dec 05 '16 at 06:25
@BasileStarynkevitch I ran it on https://www.tutorialspoint.com/compile_cpp11_online.php, it is giving me Bus error (core dumped) — Alexander Fell, Dec 05 '16 at 06:28
You're overwriting memory by assigning more strings into your `polygon1` array which only has space for 2. — acraig5075, Dec 05 '16 at 06:32
[This is a job for Vector Man!](http://en.cppreference.com/w/cpp/container/vector) — user4581301, Dec 05 '16 at 06:35
Beware of [undefined behavior](https://en.wikipedia.org/wiki/Undefined_behavior) — Basile Starynkevitch, Dec 05 '16 at 06:36

bhazero025 · Accepted Answer · 2016-12-05T06:42:25.620

I assume when you say double polygon1[2] you want to create a vector by your comment.

If you use a vector your code will work.

Also when you use a vector make sure you use vector.push_back();

#include <iostream>
#include <string>
#include <sstream>
#include <vector>

using namespace std;
bool check_if_condition(int a)
{
    string polygonString1 = "19.922379 51.666267 19.922381 51.665595 19.921547 51.665705 19.921218 51.665753 19.920787 51.665815 19.919753 51.665960 19.919952 51.666897 19.920395 51.666826 19.920532 51.667150 19.920830 51.667748 19.920989 51.667905 19.921690 51.667906 19.922141 51.662866 19.922855 51.668696 19.922664 51.668237 19.922610 51.668025 19.922464 51.667451 19.922355 51.666732 19.922379 51.666267";

    double buf1; // Have a buffer string
    stringstream ssPolygonString1(polygonString1); // Insert the string into a stream
    vector<double> polygon1; // Create vector to hold our words
    int iterPoly1 = 0;
    while (ssPolygonString1 >> buf1)
    {
        //polygon1[iterPoly1] = (buf1);
        polygon1.push_back(buf1); // Add buf1 to vector.
        cout << "buf1=" << buf1 << "\n";
        iterPoly1++;
    }
    ssPolygonString1.str("");

    //Print vector to show it works!
    for (int i = 0; i < polygon1.size(); i++)
    {
        cout << polygon1.at(i) << endl;
    }
    cout << "Return true";
    return true;
}

int main()
{
    check_if_condition(1);

    system("pause");

    return 0;
}

score 0 · Answer 2 · answered Dec 05 '16 at 06:58

0

The error is in the line: polygon1[iterPoly1]=(buf1);

because the length of vector is 2 and iterPoly is going above 2. So behaviour is unexpected.

answered Dec 05 '16 at 06:58

Amarjeet Sharma

168
1
11

Segmentation fault while returning from function in c++

2 Answers2