// For this challenge you will determine if a pair of even numbers exists somewhere in a string.
// have the function EvenPairs(str) take the str parameter being passed and determine if a pair of adjacent even numbers exists anywhere in the string. If a pair exists, return the string true, otherwise return false. For example: if str is "f178svg3k19k46" then there are two even numbers at the end of the string, "46" so your program should return the string true. Another example: if str is "7r5gg812" then the pair is "812" (8 and 12) so your program should return the string true. 

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

string EvenPairs(string str)
{
	int temp, count;

	// Loop through the string parameter
	for (int x = 0; x < str.size(); x++)
	{
		string num;
		count = 0; // Keeps count of even numbers

		// Loop checking for a sequence of number characters
		for (x; x < str.size() && str[x] >= '0' && str[x] <= '9'; x++)
		{
			// Converting current sequence of number character to an int
			num += str[x];
			istringstream(num) >> temp;

			if (temp % 2 == 0) // Validate any even numbers
			{
				num = "";
				count++;
			}
		}

		if (count >= 2)
		{
			return "true";
		}
	}
	
	return "false";
}

int main() 
{
	cout << EvenPairs("f178svg3k19k46") << endl; // true
	cout << EvenPairs("7r5gg812") << endl; // true
	cout << EvenPairs("3gy41d216") << endl; // true
	cout << EvenPairs("f09r27i8e67") << endl; // false
	cout << EvenPairs("fdfs1386eretre") << endl; // true
	return 0;

}

C Language online compiler

Write, Run & Share C Language code online using OneCompiler's C online compiler for free. It's one of the robust, feature-rich online compilers for C language, running the latest C version which is C18. Getting started with the OneCompiler's C editor is really simple and pretty fast. The editor shows sample boilerplate code when you choose language as 'C' and start coding!

Read inputs from stdin

OneCompiler's C online editor supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample C program which takes name as input and print your name with hello.

#include <stdio.h>
int main()
{
    char name[50];
    printf("Enter name:");
    scanf("%s", name);
    printf("Hello %s \n" , name );
    return 0;
    
}

About C

C language is one of the most popular general-purpose programming language developed by Dennis Ritchie at Bell laboratories for UNIX operating system. The initial release of C Language was in the year 1972. Most of the desktop operating systems are written in C Language.

Key features:

  • Structured Programming
  • Popular system programming language
  • UNIX, MySQL and Oracle are completely written in C.
  • Supports variety of platforms
  • Efficient and also handle low-level activities.
  • As fast as assembly language and hence used as system development language.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition if-else is used.

if(conditional-expression) {
   // code
} else {
   // code
}

You can also use if-else for nested Ifs and if-else-if ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to if-else-if ladder.

switch(conditional-expression) {    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
...    
    
default:     
 // code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  // code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition) {  
 // code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {
  // code 
} while (condition);

Arrays

Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.

Syntax

One dimentional Array:

data-type array-name[size];

Two dimensional array:

data-type array-name[size][size];

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity.

Two types of functions are present in C

  1. Library Functions:

Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,

  1. User defined functions:

User defined functions are the ones which are written by the programmer based on the requirement.

How to declare a Function

return_type function_name(parameters);

How to call a Function

function_name (parameters)

How to define a Function

return_type function_name(parameters) {  
  //code
}