3.4

#include <iostream>
#include <cstring>
#include <fstream>

using namespace std;
int main() {
	ifstream f("nigg1a.txt");
	if (!f) cout << "file not open\n"; else cout << "file open\n";
    char*str= new char;
      char*std= new char;
    int x,n,d;
    int c=0;
    while (!f.eof()) {f>>str; n=n+1;}
cout<<"str=" << str<<endl;
    d=strlen(str);
    cout<< "d="<<d<<endl;
    for (x=0;x!=d;x++){
if (isdigit(str[x])){std[x]=str[x];c=c+1;}
	}
	cout<<"digit is:";
	for (x=0;x!=c;x++){
		cout << std[x];
	}
}