Difference between Argument and Parameter in C/C++ with Examples

Argument

An argument is referred to the values that are passed within a function when the function is called. These values are generally the source of the function that require the arguments during the process of execution. These values are assigned to the variables in the definition of the function that is called. The type of the values passed in the function is the same as that of the variables defined in the function definition. These are also called Actual arguments or Actual Parameters.

Example: Suppose a sum() function is needed to be called with two numbers to add. These two numbers are referred to as the arguments and are passed to the sum() when it called from somewhere else.

C

// C code to illustrate Arguments

#include <stdio.h>

// sum: Function definition
int sum(int a, int b)
{
    // returning the addition
    return a + b;
}

// Driver code
int main()
{
    int num1 = 10, num2 = 20, res;

    // sum() is called with
    // num1 & num2 as ARGUMENTS.
    res = sum(num1, num2);

    // Displaying the result
    printf("The summation is %d", res);
    return 0;
}

C++

// C++ code to illustrate Arguments
#include <iostream>
using namespace std;

// sum: Function definition
int sum(int a, int b)
{
    // returning the addition
    return a + b;
}

// Driver code
int main()
{
    int num1 = 10, num2 = 20, res;

    // sum() is called with
    // num1 & num2 as ARGUMENTS.
    res = sum(num1, num2);

    // Displaying the result
    cout << "The summation is " << res;
    return 0;
}

Output:

The summation is 30

Parameters

The parameter is referred to as the variables that are defined during a function declaration or definition. These variables are used to receive the arguments that are passed during a function call. These parameters within the function prototype are used during the execution of the function for which it is defined. These are also called Formal arguments or Formal Parameters.
Example: Suppose a Mult() function is needed to be defined to multiply two numbers. These two numbers are referred to as the parameters and are defined while defining the function Mult().

C

// C code to illustrate Parameters

#include <stdio.h>

// Mult: Function definition
// a and b are the PARAMETERS
int Mult(int a, int b)
{
    // returning the multiplication
    return a * b;
}

// Driver code
int main()
{
    int num1 = 10, num2 = 20, res;

    // Mult() is called with
    // num1 & num2 as ARGUMENTS.
    res = Mult(num1, num2);

    // Displaying the result
    printf("The multiplication is %d", res);
    return 0;
}

C++

// C++ code to illustrate Parameters

#include <iostream>
using namespace std;

// Mult: Function definition
// a and b are the parameters
int Mult(int a, int b)
{
    // returning the multiplication
    return a * b;
}

// Driver code
int main()
{
    int num1 = 10, num2 = 20, res;

    // Mult() is called with
    // num1 & num2 as ARGUMENTS.
    res = Mult(num1, num2);

    // Displaying the result
    cout << "The multiplication is " << res;
    return 0;
}

Output:

The multiplication is 200

Difference between Argument and Parameter

Argument	Parameter
When a function is called, the values that are passed during the call are called as arguments.	The values which are defined at the time of the function prototype or definition of the function are called as parameters.
These are used in function call statement to send value from the calling function to the receiving function.	These are used in function header of the called function to receive the value from the arguments.
During the time of call each argument is always assigned to the parameter in the function definition.	Parameters are local variables which are assigned value of the arguments when the function is called.
They are also called Actual Parameters	They are also called Formal Parameters
Example: int num = 20; Call(num) // num is argument	Example: int Call(int rnum) { printf("the num is %d", rnum); } // rnum is parameter