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
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
std::stoi(“1”) is 1 std::stoi(“1.5”) is 1 std::stoi(“1 with words”) is 1
//源码参考cplusplus.com
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
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.”;
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本文标题: C++ 整型与字符串的互转方式
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