C++ 整型与字符串的互转方式

时间:2022-02-21 23:41:43

flyfish

字符串转整型

C的方法 cstr是char*或者const char*类型的字符串

int num = atoi(str);
int num = strtol(cstr, NULL, 10);

//10 表示进制

C++11的方法

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void test1()
std::string str1 = "1";
 
std::string str2 = "1.5";
 
std::string str3 = "1 with words";
 
 
 
int myint1 = std::stoi(str1);
 
int myint2 = std::stoi(str2);
 
int myint3 = std::stoi(str3);
 
 
std::cout << "std::stoi(\"" << str1 << "\") is " << myint1 << '\n';
 
std::cout << "std::stoi(\"" << str2 << "\") is " << myint2 << '\n';
 
std::cout << "std::stoi(\"" << str3 << "\") is " << myint3 << '\n';
}

结果输出

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std::stoi(“1”) is 1
std::stoi(“1.5”) is 1
std::stoi(“1 with words”) is 1

//源码参考cplusplus.com

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void test2()
{
 
 std::string str_dec = "2001, A Space Odyssey";
 std::string str_hex = "40c3";
 std::string str_bin = "-10010110001";
 std::string str_auto = "0x7f";
 
 std::string::size_type sz;  // alias of size_t
 
 int i_dec = std::stoi (str_dec,&sz);
 int i_hex = std::stoi (str_hex,nullptr,16);
 int i_bin = std::stoi (str_bin,nullptr,2);
 int i_auto = std::stoi (str_auto,nullptr,0);
 
 std::cout << str_dec << ": " << i_dec << " and [" << str_dec.substr(sz) << "]\n";
 std::cout << str_hex << ": " << i_hex << '\n';
 std::cout << str_bin << ": " << i_bin << '\n';
 std::cout << str_auto << ": " << i_auto << '\n';
 
 return 0;
}

输出

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2001, A Space Odyssey: 2001 and [, A Space Odyssey]
40c3: 16579
-10010110001: -1201
0x7f: 127

其他类型 类似

无符号整型

stoul

浮点型

stof

数值转字符串

std::string s;
s = std::to_string(1) + ” is int, “;

其他数值类型 类似

s = std::to_string(3.14f) + ” is float.”;

以上这篇C++ 整型与字符串的互转方式就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持服务器之家。

原文链接:https://blog.csdn.net/flyfish1986/article/details/70310741