Question

我有代码，但它以大写字母打印字母，但之后也会打印一些奇怪的字符。我只是想知道如何获得这些信件。

程序执行图片。

使用namespace std;

int main()
{

const int SIZE = 81;                                                       // Constant for size of an array
const int MIN_LOWERCASE = 97;                                              // Start of lowercase letters in ASCII
const int MAX_LOWERCASE = 122;                                             // End of lowercase letters in ASCII

char line[SIZE];                                                           // Initializing character line for input

cout << "Enter a string of 80 or fewer characters:\n";
cin.getline(line,SIZE);                                                    // Getting input from the user.

for (int count = 0; count < SIZE; count++)
{
    if (line[count] >= MIN_LOWERCASE && line[count] <= MAX_LOWERCASE)     // Checking whether the selected letter is in the reange of lowercase letters.
    {
         line[count] - 32;                                                
         cout << static_cast<char>(line[count] - 32);                     // converting and displaying lowercase letters to uppercase letters.

    }
    else
    {
        cout << static_cast<char>(line[count]);//Displaying the same character if it is in uppercase.                 

    }

}
cout << endl;


system("pause");
return 0;


}

Answer 1

您需要使用您阅读的文本的实际大小。否则，您将打印额外的字符。

for (int count = 0; count < strlen(line); count++)

您可能需要#include <cstring>才能使用strlen()。

Answer 2

cout << "Enter a string of 80 or fewer characters:\n";
cin.getline(line,SIZE);                                                    // Getting input from the user.
int strLen=strlen(line)
for (int count = 0; count < strLen; count++)
{
    if (line[count] >= MIN_LOWERCASE && line[count] <= MAX_LOWERCASE)     // Checking whether the selected letter is in the reange of lowercase letters.
    {
         line[count] - 32;                                                
         cout << static_cast<char>(line[count] - 32);                     // converting and displaying lowercase letters to uppercase letters.

    }
    else
    {
        cout << static_cast<char>(line[count]);//Displaying the same character if it is in uppercase.                 

    }

}

无论字符串大小是多少，Ypur循环都会运行80次。

Answer 3

在C ++中这样做的惯用方法是

#include <string>
#include <locale>
#include <algorithm>
#include <iterator>
#include <iostream>

int main()
{
    std::locale loc(""); //< the current system locale

    std::string line;  //< will contain the input line
    std::cout << "Enter a string of 80 or fewer characters:\n";
    std::getline(std::cin,line);

    std::string lower; //< will contain the output

    // This is the "key" of everything
    std::transform(line.begin(),line.end(), // transform the entire input...
        std::back_inserter(lower), // by writing into the back of the output string ...
        [&loc](auto c){ return std::tolower(c,loc); }); // the result of std::tolower applied to all character, using the system locale

    std::cout << "The transformed string is:\n" << lower << std::endl;

    return 0;
}

// look ma! No pointers, array sizes, overflows and explicit memory management.
// And works consistently with the language your computer is set up.

Answer 4

实际上，char []的getline / cin / scanf等函数解释如下：

为char c[10];初始化字符串。输入是＆＃34; abcd＆＃34;。
首先，c [i]初始化未知值，因为它是局部变量（如果是全局变量，则可以假设c [i] = 0）

其次，如果输入，则c [i]的值仅在0<=i<=4处改变，因为输入的长度为4。

在这种情况下，目前c = { 'a', 'b', 'c', 'd', '\0', ?, ?, ?, ?, ?}。（？表示未知值）

第三，你循环i为0到size_of_array_c，所以你的输出将是＆＃34; abcd ?????＆＃34; （我不知道？的价值。）。

因此，如果您只在c[i] != '\0'进行循环，则可以修复该错误。

我正在编写一个代码，使用数组将小写字母转换为大写字母

4 个答案: