simply read file and sum up containing numbers

Bjarne Stroustrup “Programming Principles and Practice Using C++”
Chapter 10 Exercise 1
Using std_lib_facilities.h by Bjarne Stroustrup.

[code language=”cpp”]
// Philipp Siedler
// Bjarne Stroustrup’s PPP
// Chapter 10 Exercise 1

#include "std_lib_facilities.h"

int result = 0;
string iname = "input/num.txt";
ifstream ist(iname);

void read_file() {
int temp;
if (!ist) { error("File could not be read: ", iname); }
while (ist >> temp) {
result += temp;
}
}

int main()
try
{
read_file();
cout << result << endl;
keep_window_open();
}
catch (runtime_error e) {
cout << e.what() << endl;
keep_window_open();
}
catch (…) {
cout << "Exiting" << endl;
keep_window_open();
}
[/code]

Output:
21
Please enter a character to exit
Input-File num.txt:
1 2 3 4 5 6

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