示例:C++ isdigit() #include<cctype>#include<iostream>#include<cstring>usingnamespacestd;intmain(){charstr[] ="hj;pq910js4";intcheck;cout<<"The digit in the string are:"<<endl;for(inti =0; i <strlen(str); i++) {//
In each iteration of the loop, we use the isdigit() function to check if the string element str[i] is a digit or not. The result is stored in the check variable. check = isdigit(str[i]); If check returns a non-zero value, we print the string element. if (check) cout << str...
isdigit和is_digit将变成完全相同的代码，因为它对特定的库调用进行了优化，将其转换为((unsigned)(c-4...
byte数字（单字节），全角数字（双字节），罗马数字 False: 汉字数字 Error: 无 isdecimal() True: ...
因此，理论上，两个循环应该转换成相同的代码（至少对于isdigit有这种优化的编译器--MSVC有没有，我不能...
int count_digits(const std::string& s) { return std::count_if(s.begin(), s.end(), // static_cast<int(*)(int)>(std::isdigit) // wrong // [](int c){ return std::isdigit(c); } // wrong // [](char c){ return std::isdigit(c); } // wrong [](unsigned char c){ re...
int count_digits(const std::string& s) { return std::count_if(s.begin(), s.end(), // static_cast<int(*)(int)>(std::isdigit) // wrong // [](int c){ return std::isdigit(c); } // wrong // [](char c){ return std::isdigit(c); } // wrong [](unsigned char c){ re...
g++ a.cpp a.cpp: In function 'int main(int, char**)': a.cpp:20:17: error: 'isnumber' was not declared in this scope if (isnumber(i)) { ^ 我也用clang3.8.1来测试: clang++ a.cpp --std=c++11 a.cpp:20:7: error: use of undeclared identifier 'isnumber' if (isnumber(i)) ...
123–126 \x7B–\x7E \172–\176 {|}~ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0 127 \x7F \177 backspace character (DEL) ≠0 0 0 0 0 0 0 0 0 0 0 0 Retrieved from "https://en.cppreference.com/mwiki/index.php?title=c/string/byte/isdigit&oldid=172944" Navigation...
#include #include<string> using namespace std; int main() { map<string, int>math; int answer; //bool check; math.insert(pair<string,int> ("What is 1 + 1 = ? ", 2)); math.insert(pair<string,int> ("What is 2 + 2 = ? ", 4)); math.insert(pair<string,int> ("...