提问人：Andrew 提问时间：9/11/2023 最后编辑：Mark RotteveelAndrew 更新时间：9/15/2023 访问量：69
检查字符串中的字符是否为空格不起作用
Checking whether a character in a string is a space does not work
问：
我需要在每个部分之前添加两个零，字符串中有 6 个数字，而不删除这些部分之间的空格。代码如下：
#include <iostream>
#include <string>
using namespace std;
int main()
{
string EightByte_BinaryBuffer = "010000 010100 001001 000011"; //can provide full code with reading input from user if needed
for (int i = 0; i < EightByte_BinaryBuffer.length(); i++)
{
if (i == 0)
{
EightByte_BinaryBuffer.insert(i, "00");
}
else if (isspace(EightByte_BinaryBuffer.at(i)) == true) //output console just stays black for minute without any changes
{
EightByte_BinaryBuffer.insert(i, "00");
}
}
cout << EightByte_BinaryBuffer << endl;
}
我也尝试了这个替代方案，但它也不起作用：
#include <iostream>
#include <string>
using namespace std;
int main()
{
string EightByte_BinaryBuffer = "010000 010100 001001 000011"; //can provide full code with reading input from user if needed
for (int i = 0; i < EightByte_BinaryBuffer.length(); i++)
{
if (i == 0)
{
EightByte_BinaryBuffer.insert(i, "00");
}
else if (EightByte_BinaryBuffer[i] == ' ')
{
EightByte_BinaryBuffer.insert(i, "00");
}
}
cout << EightByte_BinaryBuffer << endl;
}
对于上下文，我正在尝试复制 base64 转换器，但停留在步骤 5（将 6 位字节转换为 8 位字节）。以下是完整的算法： https://base64.guru/learn/base64-algorithm/encode
答：
0赞
Andrew
9/15/2023
#1
感谢@brian61354270指出我用“i”计数器的错误，我能够修复它：
#include <iostream>
#include <string>
using namespace std;
int main()
{
for (int i = 0; i < EightByte_BinaryBuffer.length(); i++)
{
if (i == 0)
{
EightByte_BinaryBuffer.insert(i, "00");
i += 2;
}
else if (EightByte_BinaryBuffer[i + 1] == ' ')
{
EightByte_BinaryBuffer.insert(i + 2, "00");
i += 2;
}
}
}
@paulmckenzie还建议使用输入流的替代方案：
//explanation of how this code works can be found in comments under the question
#include <iostream>
#include <string>
#include <sstream>
int main()
{
std::string EightByte_BinaryBuffer = "010000 010100 001001 000011";
std::istringstream strm(EightByte_BinaryBuffer);
std::string small_buf;
std::string new_buf;
while (strm >> small_buf)
new_buf.append("00" + small_buf + " ");
new_buf.pop_back();
std::cout << new_buf;
}
谢谢大家的帮助。
评论
ii