[英]How to convert from vector<char> to a number integer
I have a vector with [ '6' '0' '0' '0' '0'] from a user inputting 60,000. 我有一个带有['6''''0''0''0']的向量来自输入60,000的用户。 I need an int 60000 so I can manipulate this number. 我需要一个int 60000,所以我可以操纵这个数字。
I'm new to c++ and programming in general. 我是c ++和编程的新手。 I read data/numbers from 60,000-3,500,000 from a serial port and I need an integer number, the only way I have successfully done this and printed it is through std::vector. 我从一个串口读取60,000-3,500,000的数据/数字,我需要一个整数,我成功完成这个并打印它的唯一方法是通过std :: vector。 I tried to do vector but it gives me funky numbers. 我试着做矢量,但它给了我时髦的数字。
#include "SerialPort.h"
std::vector<char> rxBuf(15);
DWORD dwRead;
while (1) {
dwRead = port.Read(rxBuf.data(), static_cast<DWORD>(rxBuf.size()));
// this reads from a serial port and takes in data
// rxBuf would hold a user inputted number in this case 60,000
if (dwRead != 0) {
for (unsigned i = 0; i < dwRead; ++i) {
cout << rxBuf[i];
// this prints out what rxBuf holds
}
// I need an int = 60,000 from my vector holding [ '6' '0' '0' '0 '0']
int test = rxBuf[0 - dwRead];
cout << test;
// I tried this but it gives me the decimal equivalent of the character
numbers
}
}
I need an output of 60000 not in a vector but rather as a solid number, any help would be appreciated thanks. 我需要60000的输出不在矢量中而是作为一个实数,任何帮助将不胜感激谢谢。
From this answer , you could do something like: 从这个答案 ,你可以做一些事情:
std::string str(rxBuf.begin(), rxBuf.end());
To convert your Vector to a String. 将Vector转换为String。
After that, you could use the std::stoi function: 之后,您可以使用std :: stoi函数:
int output = std::stoi(str);
std::cout << output << "\n";
Loop over the elements of an std::vector
and construct an int
from them: 循环遍历std::vector
的元素并从中构造一个int
:
std::vector<char> chars = {'6', '0', '0', '0', '0'};
int number = 0;
for (char c : chars) {
number *= 10;
int to_int = c - '0'; // convert character number to its numeric representation
number += to_int;
}
std::cout << number / 2; // prints 30000
Use a std::string to build your string: 使用std :: string来构建字符串:
std::string istr;
char c = 'o';
istr.push_back(c);
Then use std::stoi to convert to integer; 然后使用std :: stoi转换为整数; std::stoi 的std :: Stoi旅馆
int i = std::stoi(istr);
C++17 added the std::from_chars
function that can do what you want without modifying or copying the input vector: C ++ 17添加了std::from_chars
函数,它可以执行您想要的操作而无需修改或复制输入向量:
std::vector<char> chars = {'6', '0', '0', '0', '0'};
int number;
auto [p, ec] = std::from_chars(chars.data(), chars.data() + chars.size(), number);
if (ec != std::errc{}) {
std::cerr << "unable to parse number\n";
} else {
std::cout << "number is " << number << '\n';
}
To minimize the need for temporary variables, use a std::string
with the appropriate length as a buffer. 要最小化对临时变量的需求,请使用具有适当长度的std::string
作为缓冲区。
#include "SerialPort.h"
#include <string>
std::string rxBuf(15, '\0');
DWORD dwRead;
while (1) {
dwRead = port.Read(rxBuf.data(), static_cast<DWORD>(rxBuf.size()));
if (dwRead != 0) {
rxBuf[dwRead] = '\0'; // set null terminator
int test = std::stoi(rxBuf);
cout << test;
}
}
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