Question

For some reason the following C++ code results in a segmentation fault:

#include <sstream>
#include <vector>

using namespace std;

string charToString(char c)
{
    stringstream ss;
    string s;
    ss << c;
    ss >> s;

    return s;
}

int main()
{
    vector<string> stringTable;

    for(int c = 0; c < 256; ++c){
        string s = charToString(c);
        stringTable[c] = s;
    }
}

Valgrind reports the error Invalid read of size 8 on the line

stringTable[c] = s;

But I can’t see what’s wrong with this line. So what is wrong with this code?

Answer 1

You’re writing off the end of the vector. Give the vector an initial size with

vector<string> stringTable(256);