C++ – Ascii Art in C++

ascii-artc

So I'm attempting to put in Ascii Art in a C++ program, and did so by manually printing each line, but the outcome was nothing like the ascii art. It's like:

Does this occur because the characters are not recognizable by the prompt or have I not done it correctly.
Here is the ASCII art I'm trying to do:

_____/\\\\\\\\\________/\\\\\\\\\\\__________/\\\\\\\\\__/\\\\\\\\\\\__/\\\\\\\\\\\_        
 ___/\\\\\\\\\\\\\____/\\\/////////\\\_____/\\\////////__\/////\\\///__\/////\\\///__       
  __/\\\/////////\\\__\//\\\______\///____/\\\/_______________\/\\\_________\/\\\_____      
   _\/\\\_______\/\\\___\////\\\__________/\\\_________________\/\\\_________\/\\\_____     
    _\/\\\\\\\\\\\\\\\______\////\\\______\/\\\_________________\/\\\_________\/\\\_____    
     _\/\\\/////////\\\_________\////\\\___\//\\\________________\/\\\_________\/\\\_____   
      _\/\\\_______\/\\\__/\\\______\//\\\___\///\\\______________\/\\\_________\/\\\_____  
       _\/\\\_______\/\\\_\///\\\\\\\\\\\/______\////\\\\\\\\\__/\\\\\\\\\\\__/\\\\\\\\\\\_ 
        _\///________\///____\///////////___________\/////////__\///////////__\///////////__

Code:

                cout << "_____/\\\\\\\\\________/\\\\\\\\\\\__________/\\\\\\\\\__/\\\\\\\\\\\__/\\\\\\\\\\\_        \n";
                cout << " ___/\\\\\\\\\\\\\____/\\\/////////\\\_____/\\\////////__\/////\\\///__\/////\\\///__       \n";
                cout << "  __/\\\/////////\\\__\//\\\______\///____/\\\/_______________\/\\\_________\/\\\_____      \n";
                cout << "  _\/\\\_______\/\\\___\////\\\__________/\\\_________________\/\\\_________\/\\\_____     \n";
                cout << "    _\/\\\\\\\\\\\\\\\______\////\\\______\/\\\_________________\/\\\_________\/\\\_____    \n";
                cout << "    _\/\\\/////////\\\_________\////\\\___\//\\\________________\/\\\_________\/\\\_____   \n";
                cout << "      _\/\\\_______\/\\\__/\\\______\//\\\___\///\\\______________\/\\\_________\/\\\_____  \n";
                cout << "       _\///________\///____\///////////___________\/////////__\///////////__\///////////__\n";

Best Answer

The escape sequences are interpreted as single special or other characters, hence the strange output. "\\" means '\' for example.

You can use a raw string literal:

#include <iostream>

int main()
{
    std::cout << R"(
_____/\\\\\\\\\________/\\\\\\\\\\\__________/\\\\\\\\\__/\\\\\\\\\\\__/\\\\\\\\\\\_        
 ___/\\\\\\\\\\\\\____/\\\/////////\\\_____/\\\////////__\/////\\\///__\/////\\\///__       
  __/\\\/////////\\\__\//\\\______\///____/\\\/_______________\/\\\_________\/\\\_____      
   _\/\\\_______\/\\\___\////\\\__________/\\\_________________\/\\\_________\/\\\_____     
    _\/\\\\\\\\\\\\\\\______\////\\\______\/\\\_________________\/\\\_________\/\\\_____    
     _\/\\\/////////\\\_________\////\\\___\//\\\________________\/\\\_________\/\\\_____   
      _\/\\\_______\/\\\__/\\\______\//\\\___\///\\\______________\/\\\_________\/\\\_____  
       _\/\\\_______\/\\\_\///\\\\\\\\\\\/______\////\\\\\\\\\__/\\\\\\\\\\\__/\\\\\\\\\\\_ 
        _\///________\///____\///////////___________\/////////__\///////////__\///////////__        
)" << '\n';

    return 0;
}

live demo

The original papers

C++ – Why is the program slow when looping over exactly 8192 elements

The difference is caused by the same super-alignment issue from the following related questions:

But that's only because there's one other problem with the code.

Starting from the original loop:

for(i=1;i<SIZE-1;i++) 
    for(j=1;j<SIZE-1;j++) {
        res[j][i]=0;
        for(k=-1;k<2;k++) 
            for(l=-1;l<2;l++) 
                res[j][i] += img[j+l][i+k];
        res[j][i] /= 9;
}

First notice that the two inner loops are trivial. They can be unrolled as follows:

for(i=1;i<SIZE-1;i++) {
    for(j=1;j<SIZE-1;j++) {
        res[j][i]=0;
        res[j][i] += img[j-1][i-1];
        res[j][i] += img[j  ][i-1];
        res[j][i] += img[j+1][i-1];
        res[j][i] += img[j-1][i  ];
        res[j][i] += img[j  ][i  ];
        res[j][i] += img[j+1][i  ];
        res[j][i] += img[j-1][i+1];
        res[j][i] += img[j  ][i+1];
        res[j][i] += img[j+1][i+1];
        res[j][i] /= 9;
    }
}

So that leaves the two outer-loops that we're interested in.

Now we can see the problem is the same in this question: Why does the order of the loops affect performance when iterating over a 2D array?

You are iterating the matrix column-wise instead of row-wise.

To solve this problem, you should interchange the two loops.

for(j=1;j<SIZE-1;j++) {
    for(i=1;i<SIZE-1;i++) {
        res[j][i]=0;
        res[j][i] += img[j-1][i-1];
        res[j][i] += img[j  ][i-1];
        res[j][i] += img[j+1][i-1];
        res[j][i] += img[j-1][i  ];
        res[j][i] += img[j  ][i  ];
        res[j][i] += img[j+1][i  ];
        res[j][i] += img[j-1][i+1];
        res[j][i] += img[j  ][i+1];
        res[j][i] += img[j+1][i+1];
        res[j][i] /= 9;
    }
}

This eliminates all the non-sequential access completely so you no longer get random slow-downs on large powers-of-two.

Core i7 920 @ 3.5 GHz

Original code:

8191: 1.499 seconds
8192: 2.122 seconds
8193: 1.582 seconds

Interchanged Outer-Loops:

8191: 0.376 seconds
8192: 0.357 seconds
8193: 0.351 seconds

Best Answer

Related Solutions

C++ – Image Processing: Algorithm Improvement for ‘Coca-Cola Can’ Recognition

The original papers

C++ – Why is the program slow when looping over exactly 8192 elements

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