Vectors

I have tried to run this program and every time that I do, it crashes. Do I have something wrong in my coding? Thank you for the help.

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  #include <iostream>
#include <fstream>
#include <vector>
#include <ctime>
#include <cstdlib>

using namespace std;

vector <string> noun;
vector <string> verb;
vector <string> adjective;
vector <string> article;
vector <string> adverb;
vector <string> preposition;

string nounfile = "noun.txt";
string verbfile = "verb.txt";
string adjectivefile = "adjective.txt";
string articlefile = "article.txt";
string adverbfile = "adverb.txt";
string prepositionfile = "preposition.txt";

void readFromFile(string input, vector<string> &data)
{
    ifstream in(input.c_str()); // open input file;
    string str;
    while (in >> str)
    {
    data.push_back(str);
    }
}

string readRandomWord(vector<string> data)
{
    int pos = rand() % data.size(); // get random word from vector
    return data[pos];
}

string redSays()
{
    return readRandomWord(adjective) + " " + readRandomWord(noun);
}

string greenSays()
{
    return readRandomWord(article) + " " +readRandomWord(adjective) + " " + readRandomWord(noun) + " " +readRandomWord(verb);
}

string orangeSays()
{
    return readRandomWord(verb) + " or " +readRandomWord(verb);
}

string blueSays()
{
    return readRandomWord(verb) + " " +readRandomWord(adverb);
}

string yellowSays()
{
    return readRandomWord(noun) + " and " +readRandomWord(noun);
}

string purpleSays()
{
    return readRandomWord(preposition) + " " + readRandomWord(article) + " " +readRandomWord(adjective) + " " + readRandomWord(noun);
}

string redBluePurple()
{
    return redSays() + "\n" + blueSays() + "\n" + purpleSays() + "\n"; // combine different call according to function
}

string greenYellowPurpleOrange()
{
    return greenSays() + "\n" + yellowSays() + "\n" + purpleSays() + "\n" + orangeSays() + "\n"; // combine different call according to function
}

string greenYellowRedBlueOrangePurple()
{
    return greenSays() + "\n" + yellowSays() + "\n" + redSays() + "\n" + blueSays() + "\n" + orangeSays() + "\n" + purpleSays() + "\n";
}

string randomFour()
{
    vector<int> data;
    for (int i = 0; i < 4; i++) data.push_back(rand() % 6); // generate 4 random numbers from 0 to 5
    string result = "";
    for (int i = 0; i < data.size(); i++)
    {
    switch(data[i])
    { // call corresponding function
        case 0: result += yellowSays(); break;
        case 1: result += redSays(); break;
        case 2: result += blueSays(); break;
        case 3: result += orangeSays(); break;
        case 4: result += purpleSays(); break;
        case 5: result += greenSays(); break;
    }
        result += "\n";
    }
return result;
}

int main(int argc, char*argv[])
{
    srand(time(0));
    readFromFile(nounfile, noun); // read all files create vector
    readFromFile(adjectivefile, adjective);
    readFromFile(articlefile, article);
    readFromFile(verbfile, verb);
    readFromFile(adverbfile, adverb);
    readFromFile(prepositionfile, preposition);
    int choice = 1;

    while (choice)
    {
    cout << "(1) redBluePurple\n(2) greenYellowPurpleOrange\n(3) greenYellowRedBlueOrangePurple\n(4) randomFour\n(0) Quit" << endl;
    cin >> choice;
        switch (choice)
        {
        case 1: cout << redBluePurple() << endl; break;
        case 2: cout << greenYellowPurpleOrange() << endl; break;
        case 3: cout << greenYellowRedBlueOrangePurple() << endl; break;
        case 4: cout << randomFour() << endl; break;
        case 0: exit(0);
        }
    }
return 0;
}
Where are you checking to see if your vectors actually have anything in them?
I have some .txt files that I am using.
I have some .txt files that I am using.


No doubt.

Now go back and read what @cire wrote. Try changing your readRandomWord() routine to
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string readRandomWord(vector<string> data)
{
    if ( data.size() == 0 ) cout << "This vector is EMPTY\n";
    int pos = rand() % data.size(); // get random word from vector
    return data[pos];
}
Or, to avoid accessing a non-existent element,
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string readRandomWord(vector<string> data)
{
    if ( data.size() == 0 ) 
    {
        cout << "This vector is EMPTY\n";
        return  "***EMPTY***";
    }
    int pos = rand() % data.size(); // get random word from vector
    return data[pos];
}
@lastchance,
int pos = rand() % data.size(); // get random word from vector
if data.size is 0 you invoke undefined behaviour
Thanks @Chervil, @Thomas1965.

Yes, fair comment: I shouldn't have let it get to the % data.size() line at all in that circumstance. On my system it does at least put out the error message before crashing, so I thought that was sufficient to find the bug ... if lazy on my part, since I didn't allow the program to continue gracefully. I guess that's OK if, like me, you are running from the command line: maybe not so good from an IDE.

Best to go with @Chervil's suggestion, I think.

Maybe check that the input file stream opened as well.
Last edited on
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