As I mentioned in a previous post, I will be solving challenges using C++ and Java. Earlier today I found in HackerRank a set of challenges for C++. The set seems to be split into the following categories:
- Introduction
- Strings
- Classes
- STL
- Inheritance
- Other Concepts
As usual, I like to start simple and progress towards the most complicated. In this blog entry I cover my solutions written in C++ using Microsoft Visual Studio 2013 Professional.
Challenge: Say “Hello, World!” with C++
The solution was already in the buffer:
#include <iostream>
#include <cstdio>
using namespace std;
int main() {
printf(“Hello, World!”);
return 0;
}
Challenge: Input and Output
#include <iostream>
using namespace std;
/*
*/
int main () {
int a,
b,
c;
// **** input the values ****
cin >> a >> b >> c;
// **** compute and display sum ****
int sum = a + b + c;
cout << sum << endl;
// **** ****
return 0;
}
Challenge: Basic Data Types
#include <iostream>
using namespace std;
/*
*/
int main () {
int anInt;
long aLong;
long long aLongLong;
char aChar;
float aFloat;
double aDouble;
// **** ****
int status = scanf( “%d %ld %lld %c %f %lf”,
&anInt, &aLong, &aLongLong, &aChar, &aFloat, &aDouble);
// **** ****
status = printf( “%d\n%ld\n%lld\n%c\n%.3f\n%.9lf\n”,
anInt, aLong, aLongLong, aChar, aFloat, aDouble);
// **** ****
return 0;
}
Challenge: Conditional Statements
#include <iostream>
using namespace std;
/*
*/
int main () {
// **** ****
int n;
// **** ****
cin >> n;
// **** ****
if (n == 1) {
cout << “one” << endl;
} else if (n == 2) {
cout << “two” << endl;
} else if (n == 3) {
cout << “three” << endl;
} else if (n == 4) {
cout << “four” << endl;
} else if (n == 5) {
cout << “five” << endl;
} else if (n == 6) {
cout << “six” << endl;
} else if (n == 7) {
cout << “seven” << endl;
} else if (n == 8) {
cout << “eight” << endl;
} else if (n == 9) {
cout << “nine” << endl;
} else {
cout << “Greater than 9” << endl;
}
// **** ****
return 0;
}
Challenge: For Loop
#include <iostream>
using namespace std;
/*
*/
int main () {
// **** ****
int a,
b;
// **** ****
cin >> a;
cin >> b;
// **** ****
for (int n = a; n <= b; n++) {
if (n == 1)
{
cout << “one” << endl;
}
else if (n == 2)
{
cout << “two” << endl;
}
else if (n == 3)
{
cout << “three” << endl;
}
else if (n == 4)
{
cout << “four” << endl;
}
else if (n == 5)
{
cout << “five” << endl;
}
else if (n == 6)
{
cout << “six” << endl;
}
else if (n == 7)
{
cout << “seven” << endl;
}
else if (n == 8)
{
cout << “eight” << endl;
}
else if (n == 9)
{
cout << “nine” << endl;
}
else if ((n % 2) == 1)
{
cout << “odd” << endl;
} else {
cout << “even” << endl;
}
}
// **** ****
return 0;
}
Challenge: Functions
#include <iostream>
using namespace std;
/*
*/
int max_of_four(int a, int b, int c, int d) {
int max = a;
if (b >= max) {
max = b;
}
if (c >= max) {
max = c;
}
if (d >= max) {
max = d;
}
return max;
}
/*
*/
int main () {
int a, b, c, d;
scanf(“%d %d %d %d”, &a, &b, &c, &d);
int ans = max_of_four(a, b, c, d);
printf(“%d”, ans);
// **** ****
return 0;
}
Challenge: Pointer
#include <iostream>
using namespace std;
/*
*/
void update(int *a, int *b) {
int sum = *a + *b;
int dif = *a – *b;
*a = sum;
*b = (dif >= 0) ? dif : -dif;
}
/*
*/
int main () {
int a, b;
int *pa = &a, *pb = &b;
scanf(“%d %d”, &a, &b);
update(pa, pb);
printf(“%d\n%d”, a, b);
// **** ****
return 0;
}
Challenge: Arrays Introduction
#include <iostream>
using namespace std;
/*
*/
int main () {
// **** ****
int N = 0;
cin >> N;
int arr[1000];
// **** ****
for (int i = 0; i < N; i++) {
cin >> arr[i];
}
// **** ****
for (int i = (N – 1); i >= 0; i–) {
cout << arr[i] << ” “;
}
cout << endl;
// **** ****
return 0;
}
There are a couple more challenges in the first set. Will see if I have some 
time at the end of the day; otherwise will attempt to solve them tomorrow morning.
If you have comments or questions regarding this or any other post in this blog, please do not hesitate and send me a message via email. I will not mention your name unless you explicitly tell me.
John
john.canessa@gmail.com
Follow me on Twitter: @john_canessa