1. ## Vector Image Enlarge

I'm trying to get better at C++ so I have been doing some of the challenges at topcoder.

This was the problem

Given an image as a vector <string>, scale it up by factor. That is, if the original image is M x N, the scaled image should be M*factor x N*factor. Each character in the input vector <string> should be represented by factor x factor of the same character in the output (see examples).

example

{"abc",
"def",
"ghi"}

3
Returns:
{ "aaabbbccc",
"aaabbbccc",
"aaabbbccc",
"dddeeefff",
"dddeeefff",
"dddeeefff",
"ggghhhiii",
"ggghhhiii",
"ggghhhiii" }

Here is my solution but 4 loops seems too much. Can anybody show me what I could do better? Thanks

Code:
```#include <vector>
#include <iostream>
using namespace std;

class ImageEnlarger{
public:
vector <string> enlarge(vector <string> image, int factor){
string tempImage="", tempReturn="";
vector <string> returnImage;

for(int i=0;i<image.size();i++){
tempImage=image[i];
for(int j=0;j<factor;j++){
for(int k=0;k<tempImage.length();k++){
for(int z=0;z<factor;z++){
tempReturn+=tempImage[k];
}//end for
}//end for

returnImage.push_back(tempReturn);
tempReturn="";
}//end for
}//end for

return returnImage;
}//end enlarge
};//end class```

2. Here's my take on it, although I didn't bother to make it a function or put it in a class or anything. I'm sure the scaling algorithm could be better still...and I think I miss-used the size_t type, but I'm still in the process of learning myself

EDIT: I decided to put it in function form like you did, so I'm replacing the old code with the new code. I'm just not sure it's a good idea to be passing and returning a vector this way...I believe I read that it's more efficient to pass/return an iterator instead.

Code:
```#include <iostream>
#include <string>
#include <vector>

using namespace std;

vector<string> Enlarge(const vector<string> &inImage, int scaleFactor)
{
vector<string> outImage;

size_t inWidth = inImage[0].length();  // first string determines width of image
size_t inHeight = inImage.size();
size_t outWidth = inWidth * scaleFactor;
size_t outHeight = inHeight * scaleFactor;

double step = 1.0 / scaleFactor;

for (size_t y = 0; y != outHeight; ++y)
{
string temp;
size_t yIndex = static_cast<size_t>(step * y);
for (size_t x = 0; x != outWidth; ++x)
{
size_t xIndex = static_cast<size_t>(step * x);
temp += inImage[yIndex][xIndex];
}
outImage.push_back(temp);
}

return outImage;
}

int main()
{
char *data[] = {"abc", "def", "ghi"};

size_t dataSize = sizeof(data) / sizeof(char *);

vector<string> image(data, data + dataSize);
vector<string> scaledImage;

scaledImage = Enlarge(image, 3);

// Output both image and scaledImage vectors
copy(image.begin(), image.end(), ostream_iterator<string>(cout, "\n"));
cout << endl;
copy(scaledImage.begin(), scaledImage.end(), ostream_iterator<string>(cout, "\n"));

return 0;
}```