我正在编写一个 GPA 计算器程序,我想将一个字符的值更改为不同的数字。
例如,如果用户输入字母 a
或 A
,则该值将为 4
。这就是我的程序的样子。如果我使用开关盒,我知道如何让它工作,但我想这样做。
char userInput;
char A, a = 4; // i want to change the value of A, a to 4
char B, b = 3; // i want to change the value of B, b to 3
char C, c = 2; // i want to change the value of C, c to 2
char D, d = 1; // i want to change the value of D, d to 1
char F, f = 0; // i want to change the value of F, f to 0
int count2 = 0;
int count3 = 0;
double gpa;
// the for loop is to make sure program will only run 3 times
for (int i=1; i<4;i++)
{
cout << "Test #" << i << ":" << endl;
cout << endl;
// the do while loop is being used to ensure that the user gets to
// input at least once.
do
{
cout << "Enter a Letter Grade (enter 'X' to exit): ";
cin >> userInput;
// the while loop is only being used for input valiation.
while (userInput!='A' && userInput!='a' && userInput!='B' &&
userInput!='b' && userInput!='C' && userInput!='c' &&
userInput!='D' && userInput!='d' && userInput!='F' &&
userInput!='f' && userInput !='X' && userInput !='x')
{
cout << "\n Invalid letter grade, please try again.\n";
cout << "\n Enter Letter Grade (enter 'X' to exit):";
cin >> userInput;
}
//line number 80 will add the values of the userInput together.
count2+=userInput;
// line 83 is a counter that holds the number of times the loop
// as excuted
count3++;
// line 88 will get a grade point average by dividing count3
// by count2
cout << fixed << showpoint << setprecision(2);
gpa = count2/count3;
} while(userInput !='X' && userInput!='x');
cout << "Total Grade Point: " << count2 << endl;
cout << "GPA: " << gpa << endl;
}
如果我的问题太模糊,请告诉我,以便我澄清。
最佳答案
如果您查看 ASCII 表,您会发现字母只是数字。
您可以使用简单的减法计算偏移量:
'a' - 'a' == 0
'b' - 'a' == 1
'c' - 'a' == 2
等等。要将其转换为 GPA 成绩,您可以进行简单的转换:
int deltaA = (int)('a' - 'a'); // explicit cast to int is not really needed
int max = 4;
int grade = max - deltaA;
替代解决方案是使用 map :
std::map<char, int> grades;
grades['a'] = 4;
grades['b'] = 3;
grades['c'] = 2;
...
int score = grades['a']; // score == 4
最好坚持使用大写或小写字母。您可以使用 int std::tolower(int ch)
和 int std::toupper(int ch)
函数转换它们。将 char
放入 int
是可以的 - 两者都是整数并且 int
具有更宽的范围并且 char
将适合。
反过来 - 没那么容易。 int
的范围比 char
大,您应该在转换回之前检查您的 int
值是否在 char
范围内。
关于c++ - 在 C++ 中将 char 转换为 int,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/33046348/