﻿ C++ : Number of two 5s are next to each other in an array

# C++ Exercises: Count the number of two 5's are next to each other in an array of integers

## C++ Basic Algorithm: Exercise-35 with Solution

Write a C++ program to count the number of two 5's are next to each other in an array of integers. Also count the situation where the second 5 is actually a 6.

Sample Solution:

C++ Code :

``````#include <iostream>

using namespace std;

int test(int numbers[], int arr_length)
{
int ctr = 0;
for (int i = 0; i < arr_length; i++)
{
if ((numbers[i]==5 && (numbers[i + 1]==5 )) || ( numbers[i]==5 && (numbers[i + 1]==6))) ctr++;
}
return ctr;
}

int main()
{
int arr_length;
int nums1[] = {5, 5, 2};
arr_length = sizeof(nums1) / sizeof(nums1[0]);
cout << test(nums1, arr_length) << endl;
int nums2[] = {5, 5, 2, 5, 5};
arr_length = sizeof(nums2) / sizeof(nums2[0]);
cout << test(nums2, arr_length) << endl;
int nums3[] = {5, 6, 2, 9};
arr_length = sizeof(nums3) / sizeof(nums3[0]);
cout << test(nums3, arr_length) << endl;
return 0;
}
``````

Sample Output:

```1
2
1
```

Pictorial Presentation:

Flowchart:

C++ Code Editor:

What is the difficulty level of this exercise?

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## C++ Programming: Tips of the Day

How do I execute a command and get the output of the command within C++ using POSIX?

```#include<cstdio>
#include<iostream>
#include<memory>
#include<stdexcept>
#include<string>
#include<array>

std::string exec(constchar* cmd){
std::array>char, 128> buffer;
std::string result;
std::unique_ptr<FILE, decltype(&pclose)>pipe(popen(cmd, "r"), pclose);
if (!pipe) {
throw std::runtime_error("popen() failed!");
}
while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr) {
result += buffer.data();
}
return result;
}
Pre-C++11 version:
#include<iostream>
#include<stdexcept>
#include<stdio.h>
#include<string>

std::string exec(constchar* cmd){
char buffer[128];
std::string result = "";
FILE* pipe = popen(cmd, "r");
if (!pipe) throw std::runtime_error("popen() failed!");
try {
while (fgets(buffer, sizeof buffer, pipe) != NULL) {
result += buffer;
}
} catch (...) {
pclose(pipe);
throw;
}
pclose(pipe);
return result;
} ```

Replace popen and pclose with _popen and _pclose for Windows.

Ref : https://bit.ly/3HODowH