[英]Centering Pascal's Triangle Output in C++
我已成功編寫了一個代碼,使用cout.width(total_rows - current_row)以稍微三角形的形狀輸出Pascal的三角形,但它看起來像這樣:
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
1 5 10 10 5 1
1 6 15 20 15 6 1
1 7 21 35 35 21 7 1
1 8 28 56 70 56 28 8 1
1 9 36 84 126 126 84 36 9 1
1 10 45 120 210 252 210 120 45 10 1
1 11 55 165 330 462 462 330 165 55 11 1
1 12 66 220 495 792 924 792 495 220 66 12 1
1 13 78 286 715 1287 1716 1716 1287 715 286 78 13 1
1 14 91 364 1001 2002 3003 3432 3003 2002 1001 364 91 14 1
1 15 105 455 1365 3003 5005 6435 6435 5005 3003 1365 455 105 15 1
我希望它完全集中。 我發現我可以取底行中的數字或字符,減去當前行中的字符數,然后將其除以2,得到每行所需的空格數[看起來像:cout.width( (bottow_row_characters - current_row_characters)/ 2)],但我實際上沒有實現這個想法。
我已經嘗試計算底行並在其中存儲一個字符串或數組,然后使用string.length()或sizeof(數組),但兩者都沒有效果。 (sizeof總是返回4,這是不正確的)
這是代碼:
#include <iostream>
#include <string>
using namespace std;
// Forward declaration of a function.
int Pascal (int row, int column);
/* The main function.
*
* Parameters:
* none
*
* Return value:
* 0 if we complete successfully, 1 if there was an error.
*/
int main ()
{
// introduction
cout << "\nPascal's Triangle!\n";
cout << "(Pascal's triangle is made by taking the sum of two numbers\n";
cout << "and placing that number directly underneath the two numbers.\n";
cout << "This creates a triangular array of binomial coefficients)\n\n";
// for loops to calculate and print out pascal's triangle
for (int row = 0; row <= 15; row++)
{
cout.width(16 - row);
for (int column = 0; column <= row; column++)
{
cout << Pascal(row, column) << " ";
}
cout << endl;
}
cout << endl;
}
/* This function calculates Pascal's triangle based on row and column position.
*
* Parameters:
* row, column
*
* Return value:
* the numbers in Pascal's triangle
*/
int Pascal (int row, int column)
{
// if statements to calculate pascal's triangle through recursion
if (column == 0)
return 1;
else if (row == column)
return 1;
else
return Pascal(row - 1, column - 1) + Pascal(row - 1, column);
}
我想到了。 您必須使用stringstream庫將Pascal函數中的整數行轉換為字符串。 然后,您可以使用string.length()來確定字符串中有多少個字符。 然后你做我之前解釋的數學來調整輸出。
這是我的代碼:
/*
* Pascal's Triangle: Prints the first 15 rows of Pascal's triangle.
*
*/
#include <iostream>
#include <string>
#include <iomanip>
#include <sstream>
using namespace std;
// Forward declaration of a function.
int Pascal (int row, int column);
int rowLength (int row, int column);
/* The main function.
*
* Parameters:
* none
*
* Return value:
* 0 if we complete successfully, 1 if there was an error.
*/
int main ()
{
// introduction
cout << "\nPascal's Triangle!\n";
cout << "(Pascal's triangle is made by taking the sum of two numbers\n";
cout << "and placing that number directly underneath the two numbers.\n";
cout << "This creates a triangular array of binomial coefficients)\n\n";
// determination of how long the bottom row is
int bottom_row;
string bottom_row_characters;
stringstream out;
for (int row = 15; row <= 15; row++)
{
for (int column = 0; column <= row; column++)
{
out << " " << Pascal(row, column) << " ";
}
bottom_row_characters += out.str();
}
// for loops to calculate and print out pascal's triangle
for (int row = 0; row <= 15; row++)
{
cout.width((bottom_row_characters.length() - rowLength(row, 0)) / 2);
for (int column = 0; column <= row; column++)
{
cout << " " << Pascal(row, column) << " ";
}
cout << endl;
}
cout << endl;
}
/* This function calculates Pascal's triangle based on row and column position.
*
* Parameters:
* row, column
*
* Return value:
* the numbers in Pascal's triangle
*/
int Pascal (int row, int column)
{
// if statements to calculate pascal's triangle through recursion
if (column == 0)
return 1;
else if (row == column)
return 1;
else
return Pascal(row - 1, column - 1) + Pascal(row - 1, column);
}
/* This function converts a row from Pascal's Triangle from integers to a string
*
* Parameters:
* row, column
*
* Return value:
* a string representing a row in Pascal's triangle
*/
int rowLength (int row, int column)
{
int current_row;
string current_row_characters;
stringstream out;
for (int current_row = row; current_row <= row; current_row++)
{
for (int column = 0; column <= row; column++)
{
out << " " << Pascal(row, column) << " ";
}
current_row_characters += out.str();
}
return current_row_characters.length();
}
使用std::setw
使所有輸出恆定寬度:
cout << setw(5);
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.