# reverse integer sequence

Bjarne Stroustrup “Programming Principles and Practice Using C++”
Chapter 8 Exercise 5
Using std_lib_facilities.h by Bjarne Stroustrup.

main.cpp main file

[code language=”cpp”]
// Philipp Siedler
// Bjarne Stroustrup’s PP
// Chapter 8 Exercise 5

#include "std_lib_facilities.h"

vector<int> myVec{ 0,1,2,3,4,5,6,7,8,9 };
vector<int> myVecRev;

class Rev {

public:
vector<int> v;
vector<int> vr;

Rev(vector<int>& _v, vector<int>& _vr) :v(_v), vr(_vr) {};
void reverse();
void reverseSame();
void printV(string&);
void printVR(string&);
};

void Rev::reverse() {
for (int i = 0; i < v.size(); i++) {
vr.push_back(v[(v.size() – 1) – i]);
}
}

void Rev::reverseSame() {
for (int i = 0; i < v.size() / 2; i++) {
int temp;
temp = v[i];
v[i] = v[(v.size() – 1) – i];
v[(v.size() – 1) – i] = temp;
}
}

void Rev::printV(string& _label) {
for (int x : v) {
cout << _label << " " << x << "\n";
}
}

void Rev::printVR(string& _label) {
for (int x : vr) {
cout << _label << " " << x << "\n";
}
}

int main()
try
{
string label = "l";
Rev rev(myVec, myVecRev);
cout << "First version:\n";

rev.reverse();
rev.printV(label);
rev.printVR(label);

cout << "Second version:\n";

rev.reverseSame();
rev.printV(label);

keep_window_open();

}

catch (runtime_error e) {
cout << e.what() << "\n";
keep_window_open();
}

catch (…) {
cout << "Exiting\n";
keep_window_open();
}
[/code]

```Output:
First version:
l 0
l 1
l 2
l 3
l 4
l 5
l 6
l 7
l 8
l 9
l 9
l 8
l 7
l 6
l 5
l 4
l 3
l 2
l 1
l 0
Second version:
l 9
l 8
l 7
l 6
l 5
l 4
l 3
l 2
l 1
l 0
Please enter a character to exit
```