/* Prime factorisation This program will output the prime factorisation of any given integer greater then 1. Exemple: Input: 459 Output: 459 = 3^3 * 17 */ #include #include #include #include #include #include auto prime = [](int n) { if(n==2 || n==3) return 1; for(int i(2);i!=n/2+1;i++){ if(!(n%i)) return 0; } return 1; };//lambda function std::vector v;//external "global" container int rec(int n){ if(n<2 || prime(n)){ v.push_back(n); return n; } int i(2); for(;i<=n/2;i++){ if(!(n%i) && prime(i)){ v.push_back(i); n/=i; } } rec(n);//we repeat it until n<2 or is prime } std::vector func(int n){ if(prime(n) && n<10){ v.insert(v.end(),{n,1});//insert at the end return v; }else if(n<2) throw 42;//throw an error else{ rec(n); return v; } } std::map prime_fact(int n){ std::map r; std::vector f = func(n); for_each(f.begin(), f.end(),[&r](int i){r[i]++;});//map containing the value as key and the number of times it appears as value return r; } int main() { try{ int b; std::cin>>b; std::map u=prime_fact(b); std::stringstream sr; sr< key //p.second => value } std::string s = sr.str(); s=s.substr(0,s.length()-2);//take out the last " * " std::cout<

prime_fact.cpp