by Dinesh Thakur Category: Function and Pointer

Argument: An argument is an expression which is passed to a function by its caller (or macro by its invoker) in order for the function(or macro) to perform its task. It is an expression in the comma-separated list bound by the parentheses in a function call expression.

Actual arguments:

The arguments that are passed in a function call are called actual arguments. These arguments are defined in the calling function.

Formal arguments:

The formal arguments are the parameters/arguments in a function declaration. The scope of formal arguments is local to the function definition in which they are used. Formal arguments belong to the called function. Formal arguments are a copy of the actual arguments. A change in formal arguments would not be reflected in the actual arguments.


#include <stdio.h>

void sum(int i, int j, int k);

/* calling function */

int main()


      int a = 5;

      // actual arguments

      sum(3, 2 * a, a);

      return 0;


/* called function */

/* formal arguments*/

void sum(int i, int j, int k)


       int s;

       s = i + j + k;

       printf("sum is %d", s);



Here 3,2*a,a are actual arguments and i,j,k are formal arguments.

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Dinesh ThakurDinesh Thakur holds an B.C.A, MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.

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