C++ program creates a function with parameters and return value

Any programming language that uses functions has code that is simpler, more modular, and easier to change while debugging. Functions are very useful components in modular code. The ability of a function to accept parameters and output results. Functions don't necessarily need to accept input and always produce a result. In many cases, functions only accept some input and return nothing. Not always responsive and will not tolerate controversy. This article explains how to create a C program that uses functions that accept multiple parameters and produce a result after processing.

Function with parameters and return value

To define a function that takes several parameters and returns a value to the caller function (the caller function is the caller function that calls our function to perform some operation), the return type must be a specific type, not void , and the given parameter list must be present in the parameter list

grammar

<return type> function_name ( <type1> argument1, <type2> argument2, … ) {
   // function body
}

In the following example, we pass a number as a parameter, then calculate the factorial of the given number and return the result. Let's look at the algorithm and implementation in C.

algorithm

• Define a function Factorial(), which will take n as a parameter
• Facts: = 1
• When n > 1; do
  • fact = fact * n
  • n = n - 1
• Finish
• Return facts
• End function body
• Call Factorial() and pass n to find the factorial of n

Example

#include <iostream>
using namespace std;

long factorial( int n ) {
   long fact = 1;
   while ( n > 1 ) {
      fact = fact * n;
      n = n - 1;
   }
   return fact;
}

int main()
{
   cout << "Factorial of 6 is: ";
   long res = factorial( 6 );
   cout << res << endl;
   cout << "Factorial of 8 is: ";
   res = factorial( 8 );
   cout << res << endl;
   cout << "Factorial of 12 is: ";
   res = factorial( 12 );
   cout << res << endl;
}

Output

Factorial of 6 is: 720
Factorial of 8 is: 40320
Factorial of 12 is: 479001600

Another example of using a function to check if a number is a palindrome. We pass a number as parameter and the function will return true when it is a palindrome and false when it is not a palindrome.

algorithm

• Define a function solve(), which will require n
• Sum: = 0
• temp = n;
• When n > 0, execute
  • rem := n mod 10
  • Sum := (sum * 10) rem
  • n := Lower limit of (n / 2)
• Finish
• If sum is the same as temp, then
  • return true
• otherwise
  • Return error
• If it ends

Example

#include <iostream>
#include <sstream>

using namespace std;
string solve( int n ) {
   int sum = 0;
   int temp = n;
   int rem;
   while( n > 0) {
      rem = n % 10;
      sum = (sum * 10) + rem;
      n = n / 10;
   }

   if( temp == sum ) {
      return "true";
   }
   else {
      return "false";
   }
}

int main()
{
   cout << "Is 153 a palindrome? " << solve( 153 ) << endl;
   cout << "Is 15451 a palindrome? " << solve( 15451 ) << endl;
   cout << "Is 979 a palindrome? " << solve( 979 ) << endl;
}

Output

Is 153 a palindrome? false
Is 15451 a palindrome? true
Is 979 a palindrome? true

in conclusion

Using functions when writing code modularizes the code and has several advantages when debugging or working with other people's code. There are different function patterns, sometimes taking parameters from the caller function and returning the results to the caller function. Sometimes it takes no input but returns a value. In this article, we saw through a few examples how to write a function that takes parameters and returns a value to the caller function. Using functions is very simple and easy to implement. It's always good to use functions when writing code, as this can reduce unnecessary code duplication in many applications.

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