#include <iostream>
#include <cassert>
using namespace std;
//constants:
const int MIN_HEIGHT = 3;
const int MIN_WIDTH = 3;
const int MAX_HEIGHT = 20;
const int MAX_WIDTH = 60;
const char H = 'h';
const char W = 'w';
const char B = 'b';
const char F = 'f';
const char Q = 'q';
//prototypes:
void drawRectangle(int row, int col, char border, char fill);
void displayChoices();
char getChoice(char h, char w, char b, char f, char q);
int main()
{
char border, fill, choice;
cout << endl << "Welcome! \n";
drawRectangle (10,10, '#','*');
cout << endl << "Choose from the following: \n";
displayChoices();
getChoice(H, W, B, F, Q);
//drawRectangle();//not sure how to get the changed value from getChoice
//if height is changed, update height. If width is changed, update width of rect.
//if border is changed, update rectangle border. If fill is changed, update rectangle fill
}
//draws rectangle
void drawRectangle(int row, int col, char border, char fill)
{
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
if ((i == 0) || (i == (row - 1)) || (j == 0) || (j == (col - 1))) {
cout << border;
}
else {
cout << fill;
}
}
cout << endl;
}
}
//diplays users choices between height, width
//border and quit
void displayChoices()
{
cout << "h) Change the height.\n";
cout << "w) Change the width.\n";
cout << "b) Change the border character.\n";
cout << "f) Change the fill character.\n";
cout << "q) Quit program.\n";
}
//takes users choice and asks for the new value or character
char getChoice(char h, char w, char b, char f, char q) {
char choice, newBorder, newFill;
int newHeight, newWidth, count = 0;
cin >> choice;
while ((choice != h && choice != w && choice != b && choice != f && choice != q)) {
cout << "Not a valid choice. Choose again.\n";
cin >> choice;
}
if (choice == q)
return 0;
else if (choice == h) {
cout << "Enter new height between " << MIN_HEIGHT << " and " << MAX_HEIGHT << ": \n";
cin >> newHeight;
while ((newHeight < MIN_HEIGHT) || (newHeight > MAX_HEIGHT)) {
cout << "That number is not in range. Try again.\n";
cout << "Enter a number between " << MIN_HEIGHT
<< " and " << MAX_HEIGHT << ": ";
cin >> newHeight;
} return newHeight;
}
else if (choice == w) {
cout << "Enter new width between " << MIN_WIDTH << " and " << MAX_WIDTH << ": \n";
cin >> newWidth;
while ((newWidth < MIN_WIDTH) || (newWidth > MAX_WIDTH)) {
cout << "That number is not in range. Try again.\n";
cout << "Enter a number between " << MIN_WIDTH
<< " and " << MAX_WIDTH << ": ";
cin >> newWidth;
} return newWidth;
}
else if (choice == b) {
cout << "Enter new border character: \n";
cin >> newBorder;
return newBorder;
}
else if (choice == f) {
cout << "Enter new fill character: \n";
cin >> newFill;
return newFill;
}
}
我正在尝试创建一个绘制矩形的应用程序，用户可以更改矩形的高度，宽度，边框和填充（一次一个）。我无法理解如何访问/保存用户的输入（更改为矩形）以及使用更新的值绘制新矩形。我刚刚学习C ++，所以我的代码甚至可能不是解决这个问题的正确方法。任何帮助或指导表示赞赏。
答案 0 :(得分：0)
如果您不熟悉用C ++定义函数，我当然会建议您尝试一些较小的程序。
您定义为函数getChoice(char, char, char, char, char)的返回类型的类型是char，但函数中的所有返回值（newBorder除外）都是int类型，这是不合适的。< / p>
事实上，从你的函数“getChoice”的名称判断，该函数应该只返回用户的“选择”而不是更进一步，并且应该在别处进行进一步的指示。
当用户输入'q'时，getChoice中的return 0语句不会导致main函数退出，而只会导致getChoice函数返回int值为0。
在判断用户的选择时，我还考虑比所有if-else语句更好的switch-case语句。
在我根据您的程序编写的以下代码中，在main函数内执行了进一步的指令。
#include <iostream>
#include <cassert>
using namespace std;
//constants:
const int MIN_HEIGHT = 3;
const int MIN_WIDTH = 3;
const int MAX_HEIGHT = 20;
const int MAX_WIDTH = 60;
const char H = 'h';
const char W = 'w';
const char B = 'b';
const char F = 'f';
const char Q = 'q';
//prototypes:
void drawRectangle(int row, int col, char border, char fill);
void displayChoices();
char getChoice(char h, char w, char b, char f, char q);
int main()
{
char border = '#', fill = '*', choice;
int newHeight = 0;
int newWidth = 0;
char newBorder = (char)0;
char newFill = (char)0;
int height = 10, width = 10;
cout << endl << "Welcome! \n";
while (true)
{
drawRectangle(height, width, border, fill);
cout << endl << "Choose from the following: \n";
displayChoices();
choice = getChoice(H, W, B, F, Q);
//if height is changed, update height. If width is changed, update width of rect.
//if border is changed, update rectangle border. If fill is changed, update rectangle fill
switch (choice)
{
case Q:
return 0;
case H:
cout << "Enter new height between " << MIN_HEIGHT << " and " << MAX_HEIGHT << ": \n";
cin >> newHeight;
while ((newHeight < MIN_HEIGHT) || (newHeight > MAX_HEIGHT)) {
cout << "That number is not in range. Try again.\n";
cout << "Enter a number between " << MIN_HEIGHT
<< " and " << MAX_HEIGHT << ": ";
cin >> newHeight;
}
height = newHeight;
break;
case W:
cout << "Enter new width between " << MIN_WIDTH << " and " << MAX_WIDTH << ": \n";
cin >> newWidth;
while ((newWidth < MIN_WIDTH) || (newWidth > MAX_WIDTH)) {
cout << "That number is not in range. Try again.\n";
cout << "Enter a number between " << MIN_WIDTH
<< " and " << MAX_WIDTH << ": ";
cin >> newWidth;
}
width = newWidth;
break;
case B:
cout << "Enter new border character: \n";
cin >> newBorder;
border = newBorder;
break;
case F:
cout << "Enter new fill character: \n";
cin >> newFill;
fill = newFill;
break;
}
}
return 0;
}
//draws rectangle
void drawRectangle(int row, int col, char border, char fill)
{
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
if ((i == 0) || (i == (row - 1)) || (j == 0) || (j == (col - 1))) {
cout << border;
}
else {
cout << fill;
}
}
cout << endl;
}
}
//diplays users choices between height, width
//border and quit
void displayChoices()
{
cout << "h) Change the height.\n";
cout << "w) Change the width.\n";
cout << "b) Change the border character.\n";
cout << "f) Change the fill character.\n";
cout << "q) Quit program.\n";
}
//takes users choice and asks for the new value or character
char getChoice(char h, char w, char b, char f, char q) {
char choice, newBorder, newFill;
int newHeight, newWidth, count = 0;
cin >> choice;
while ((choice != h && choice != w && choice != b && choice != f && choice != q)) {
cout << "Not a valid choice. Choose again.\n";
cin >> choice;
}
return choice;
}
使用'using namespace std;'实际上也是一种不好的做法。声明，但它可以为初学者减少很多麻烦，所以你现在不需要关心它。请记住，你应该在一段时间后摆脱它。