我正在尝试制作一个程序,当用户输入一些愚蠢的内容时,该程序不接受代码错误。比如将一个整数放入一个字符串,我现在不知道该怎么办。我正在随机写下一些内容,因为它说我没有足够的细节,即使我此时已经写了整个段落。
void scoretoletter::letter() {
int a = 0;
int question;
while (a == 0) {
cout << "1.Rectangle" << endl;
cout << "2.Triangle" << endl;
cout << "3.Circle" << endl;
cout << "4.Exit" << endl;
float area;
float Width;
float Length;
float Height;
float base;
float radius;
int l;
cin >> question;
if (question == 1) {
cout << "Whats your length?" << endl;
cin >> Length;
if (cin.fail()) {
cout << "That is not valid try again" << endl;
}
else {
cout << "Whats your width?" << endl;
cin >> Width;
if (cin.fail()) {
cout << "That is not valid try again" << endl;
}
else {
if (Length == 0 || Width == 0 ) {
cout << "That is not valid try again." << endl;
system("pause");
}
else {
area = Length * Width;
cout << "The area is: " << area << endl;
}
}
}
}
else if (question == 2) {
cout << "What is the Base?" << endl;
cin >> base;
if (cin.fail()) {
cout << "That is not valid try again." << endl;
}
else {
cout << "What is the Height?" << endl;
cin >> Height;
if (cin.fail()) {
cout << "That is not valid try again." << endl;
}
else {
if (base == 0 || Height == 0 || cin.fail()) {
cout << "That is not valid try again." << endl;
system("pause");
}
else {
area = base * Height * .5;
cout << "The area is: " << area << endl;
}
}
}
}
else if (question == 3) {
cout << "What is the radius?" << endl;
cin >> radius;
if (radius == 0 || cin.fail()) {
cout << "That is not valid try again." << endl;
system("pause");
}
else {
area = radius * radius * 3.14;
cout << "The area is: " << area << endl;
}
}
else if (question == 4) {
a = 1;
}
else {
cout << "That is not valid try again." << endl;
}
system("pause");
}
}
最佳答案
您可以使用 return
指令来编写更简单的代码,而不是使用如此深层嵌套的丑陋的 if-else 语法。为了避免重复,您还可以返回状态并循环直到成功。
enum result_status
{
RESULT_STATUS_OK,
RESULT_STATUS_INVALID,
RESULT_STATUS_DONE
}
void scoretoletter::askQuestions() {
while(true)
switch(letter())
{
RESULT_STATUS_OK:
system("pause");
continue;
RESULT_STATUS_INVALID:
cout << "That is not valid try again." << endl;
system("pause");
cin.clear();
continue;
RESULT_STATUS_DONE:
system("pause");
return;
}
}
enum result_status scoretoletter::letter() {
int question;
cout << "1.Rectangle" << endl;
cout << "2.Triangle" << endl;
cout << "3.Circle" << endl;
cout << "4.Exit" << endl;
float area;
float Width;
float Length;
float Height;
float base;
float radius;
int l;
cin >> question;
if (question == 1) {
cout << "Whats your length?" << endl;
cin >> Length;
if (cin.fail())
return RESULT_STATUS_INVALID;
cout << "Whats your width?" << endl;
cin >> Width;
if (cin.fail() || Length == 0 || Width == 0)
return RESULT_STATUS_INVALID;
area = Length * Width;
cout << "The area is: " << area << endl;
return RESULT_STATUS_OK;
}
if (question == 2) {
cout << "What is the Base?" << endl;
cin >> base;
if (cin.fail())
return RESULT_STATUS_INVALID;
cout << "What is the Height?" << endl;
cin >> Height;
if (cin.fail())
return RESULT_STATUS_INVALID;
if (base == 0 || Height == 0 || cin.fail()) {
return RESULT_STATUS_INVALID;
area = base * Height * .5;
cout << "The area is: " << area << endl;
return RESULT_STATUS_OK;
}
if (question == 3) {
cout << "What is the radius?" << endl;
cin >> radius;
if (radius == 0 || cin.fail()) {
return RESULT_STATUS_INVALID;
area = radius * radius * 3.14;
cout << "The area is: " << area << endl;
return RESULT_STATUS_OK;
}
if (question == 4)
return RESULT_STATUS_DONE;
return RESULT_STATUS_INVALID;
}
请注意使用system("pause");
也是一个坏主意,您确实应该在程序中编写自己的按任意键继续
功能。
关于C++ cin.fail() while 循环,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/46086077/