new to programming so I apologize if this has been answered before...I have tried searching with almost zero luck. I am trying to create a number pattern like 1,2,2,3,3,3,4,4,4,4 etc; I have gotten to that point but I need to put it into a string vector so that if the user inputs 5, the string vector elements are 1,2,2,3,3,3,4,4,4,4,5,5,5,5,5

void print_vectorStr(vector<string> &vec, string sep = "")
{
    cout << "\nThe vector string elements are: ";
    for (auto elem : vec)
    {
        cout << elem << sep;
    }
    cout << endl;
}

void print_vector(vector<int> &vec, string sep = "")
{
    cout << "\nThe vector integer elements are: ";
    for (auto elem : vec)
    {
        cout << elem << sep;
    }
    cout << endl;
}

int main()
{

    int n;
    cout << "insert n \n";
    cin >> n;

    vector<int> vec(n);
    vector<string> vecString;
    for (int i = 1; i <= vec.size(); i  )
    {
        for (int j = 1; j <= i; j  )
        {
            cout << i << " ";
        }
    }

    print_vector(vec, " ");
    print_vectorStr(vecString, " ");

    return 0;
}

CodePudding user response：

If you really need a vector of strings, and need to reproduce the output in a comma-separated pattern, you can do something simple like:

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

int main () {
  
  size_t n = 0;                           /* unsigned variable for n */
  std::vector<std::string> pattern{};     /* vector of strings */
  
  std::cout << "enter n: ";
  if (!(std::cin >> n)) {                 /* validate EVERY user-input */
    std::cerr << "error: invalid input.\n";
    return 1;
  }
  
  for (size_t i = 0; i <= n; i  ) {           /* loop n times from 1 */
    for (size_t j = 0; j < i; j  ) {          /* loop i times */
      pattern.push_back(std::to_string(i));   /* add i i's to string */
    }
  }
  
  /* loop over each string in pattern with index to control ',' output */
  for (size_t i = 0; i < pattern.size(); i  ) {
    if (i) {                    /* if not first string */
      std::cout.put(',');       /* output ',' */
    }
    std::cout << pattern[i];    /* output string */
  }
  std::cout.put('\n');          /* tidy up with newline */
}

Note above you must validate EVERY user-input. Otherwise, what would happen if the user slipped and tapped 't' instead of 5? Also note, to control the ',' separator for output, you can either keep a counter and use a range-based for loop, or, since you need a counter anyway, just use a normal conditioned for loop.

Example Use/Output

$ ./bin/num_pattern
enter n: 2
1,2,2

$ ./bin/num_pattern
enter n: 5
1,2,2,3,3,3,4,4,4,4,5,5,5,5,5

or

$ ./bin/num_pattern
enter n: t
error: invalid input.

Look things over and let me know if you have further questions.

CodePudding user response：

I need to put it into a string vector

You can use std::vector::push_back to add(push_back) more elements into a vector as shown below. Moreover, you can use std::to_string to convert the int to std::string. Also note that there is no need to create a std::vector<int>. You can just directly use push_back to push/add elements into vecString using to_string as shown below:

#include <iostream>
#include<algorithm>
#include<string>
#include<vector>

void print_vectorStr(const std::vector<std::string> &vec, std::string sep = "")
{
    std::cout << "\nThe vector string elements are: ";
    for (auto elem : vec)
    {
        std::cout << elem << sep;
    }
    std::cout << std::endl;
}

int main()
{

    int n;
    std::cout << "insert n \n";
    std::cin >> n;

    std::vector<std::string> vecString;
    for (int i = 1; i <= n; i  )
    {
        for (int j = 1; j <= i; j  )
        {
            
            vecString.push_back(std::to_string(i)); //add element into the vecString
        }
    }
    
    print_vectorStr(vecString, " ");//prints the required pattern

}

Demo