加速C++练习2.4

我已经学习Accelerated C++好几个星期了，但我已经在练习2.4上坚持了一段时间，最后我想我找到了它，但在尝试给它不同的维度后，我发现它并没有真正起作用，我真的不明白为什么

代码最初打印一条带边框的消息，在这个特定的练习中，我应该改变代码打印空白的方式，从一次打印一个字符变成一次写下所有的木板

这是代码：

// [2-0, 2-4] Exercises
#include<iostream>
#include<string>
// saying what standard-library names we use
using std::cout;        using std::endl;
using std::cin;         using std::string;
int main()
{
// asking for the name
cout << "Please enter your first name: ";
// reading the name
string name;
cin >> name;
// building the message that we intend to write
const string greeting = "Hello, " + name + "!";
//  2.2 & 2.3 asking for inpadY
cout << "Please enter the number of padY (Vertical padding): ";
// 2.2 & 2.3 reading the inpadY
int inpadY;
cin >> inpadY;
//  2.2 & 2.3 asking for inpadX
cout << "Please enter the number of padX (Horizontal padding): ";
// 2.2 & 2.3 reading the inpadX
int inpadX;
cin >> inpadX;
// the number of planks surrounding the greeting
// 2.2 & 2.3 added inpadY as the number of planks;
const int padY = inpadY;
// 2.2 & 2.3 added inpadX
const int padX = inpadX;
// 2.4 pad size
const int pad = inpadX + inpadY;
// the number of rows and columns to write
const int rows = padY * 2 + 3;
const string::size_type cols = greeting.size() + padX * 2 + 2;
// 2.4 creating a padding string left and right and top and bottom
const string LeftRightPad(padY, ' ');
const string TopBottomPad(cols - 2, ' ');
// write a blank line to separate the output and the input
cout << endl;
// write rows rows of output
// invariant: we have written r rows so far
for (int r = 0; r != rows; ++r) {
string::size_type c = 0;
// invariant: we have written c characters so far in the current row
while (c != cols) {
// is it time to write the greeting?
if (r == padY + 1 && c == padX + 1)
{
cout << greeting;
c += greeting.size();
} else {
// are we on the border?
if (r == 0 || r == rows - 1 ||
c == 0 || c == cols - 1)
{cout << "*";
++c;}
else
// 2.4 typing out the spaces at once
{cout << LeftRightPad;
c += LeftRightPad.size();}
}
}
cout << endl;
}
return 0;
}

编辑为具有输入和输出

Please enter your first name: Estrogen
Please enter the number of padY (Vertical padding): 2
Please enter the number of padX (Horizontal padding): 2
**********************
*                    *
*                    *
*  Hello, Estrogen!  *
*                    *
*                    *
**********************
Process returned 0 (0x0)   execution time : 3.281 s
Press any key to continue.

Please enter your first name: Estrogen
Please enter the number of padY (Vertical padding): 2
Please enter the number of padX (Horizontal padding): 5
****************************
*                          *
*                          *
*                          *
*                          *
*                          *
****************************
Process returned 0 (0x0)   execution time : 5.098 s
Press any key to continue.

Please enter your first name: Estrogen
Please enter the number of padY (Vertical padding): 3
Please enter the number of padX (Horizontal padding): 2
**********************
*
*
*
*
*
*
*
**********************
Process returned 0 (0x0)   execution time : 4.333 s
Press any key to continue.

更新：我已经重写了代码，输出是一个星号的无限循环，这里是新代码

#include<iostream>
#include<string>
using std::string;      using std::endl;
using std::cout;        using std::cin;
int main()
{
cout << "Please enter your first name: ";
string name;
cin >> name;
const string message = "Hello, " + name + "!";
cout << "Enter the length: ";
int length;
cin >> length;
cout << "Enter the height: ";
int height;
cin >> height;
const int rows = height * 2 + 3;
const string::size_type cols = message.size() + length * 2 + 2;
const string TopBottom(cols, '*');
const string Blank(cols - 2, ' ');
const string messageblank(cols - 3 - message.size(), ' ');
cout << endl;

for (int r = 0; r != rows; ++r) {
string::size_type c = 0;
while (c != cols) {
if ( r == height + 1 && c == length + 1)
{
cout << messageblank << message << messageblank;
c += Blank.size();
} else
if (r == 0 && c == 0 || r == rows - 1 && c == cols -1)
{
cout << TopBottom;
c += TopBottom.size();
} else
if ( r != 0 && c == 0 || r != rows -1 && c == cols - 1)
{
cout << "*";
++c;
} else
cout << Blank;
c += Blank.size();
}
cout << endl;
}

return 0;
}

感谢你们提前帮助