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In mathematics, c-function may refer to:

Smooth function
Harish-Chandra's c-function in the theory of Lie groups
List of C functions for the programming language C

This disambiguation page lists mathematics articles associated with the same title.
If an internal link led you here, you may wish to change the link to point directly to the intended article.

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+In mathematics, '''c-function''' may refer to:
-A function is a module or block of program code which deals with a particular task. Making functions is a way of isolating one block of code from other independent blocks of code.
+*[[Smooth function]]
+*[[Harish-Chandra's c-function]] in the theory of Lie groups
+*[[List of C functions]] for the programming language C
+{{Mathdab}}
+{{Short pages monitor}}<!-- This long comment was added to the page to prevent it from being listed on Special:Shortpages. It and the accompanying monitoring template were generated via Template:Long comment. Please do not remove the monitor template without removing the comment as well.-->
-Functions serve two purposes.
-They allow a programmer to say: `this piece of code does a specific job which stands by itself and should not be mixed up with anyting else',
-Second they make a block of code reusable since a function can be reused in many different contexts without repeating parts of the program text.
-A function can take a number of parameters, do required processing and then return a value. There may be a function which does not return any value.
-You already have seen couple of built-in functions like printf(); Similar way you can define your own functions in C language.
-Consider the following chunk of code
-   int total = 10;
-   printf("Hello World");
-   total = total + l;
-To turn it into a function you simply wrap the code in a pair of curly brackets to convert it into a single compound statement and write the name that you want to give it in front of the brackets:
-Demo()
-{
-   int total = 10;
-   printf("Hello World");
-   total = total + l;
-}
-curved brackets after the function's name are required. You can pass one or more paramenters to a function as follows:
-Demo( int par1, int par2)
-{
-   int total = 10;
-   printf("Hello World");
-   total = total + l;
-}
-By default function does not return anything. But you can make a function to return any value as follows:
-int Demo( int par1, int par2)
-{
-   int total = 10;
-   printf("Hello World");
-   total = total + l;
-   return total;
-}
-A return keyword is used to return a value and datatype of the returned value is specified before the name of function. In this case function returns total which is int type. If a function does not return a value then void keyword can be used as return value.
-Once you have defined your function you can use it within a program:
-main()
-{
-  Demo();
-}
-Functions and Variables:
-Each function behaves the same way as C language standard function main(). So a function will have its own local variables defined. In the above example total variable is local to the function Demo.
-A global variable can be accessed in any function in similar way it is accessed in main() function.
-Declaration and Definition
-When a function is defined at any place in the program then it is called function definition. At the time of definition of a function actual logic is implemented with-in the function.
-A function declaration does not have any body and they just have their interfaces.
-A function declaration is usually declared at the top of a C source file, or in a separate header file.
-A function declaration is sometime called function prototype or function signature. For the above Demo() function which returns an integer, and takes two parameters a function declaration will be as follows:
-int Demo( int par1, int par2);
-Passing Parameters to a Function
-There are two ways to pass parameters to a function:
-Pass by Value: mechanism is used when you don't want to change the value of passed paramters. When parameters are passed by value then functions in C create copies of the passed in variables and do required processing on these copied variables.
-Pass by Reference mechanism is used when you want a function to do the changes in passed parameters and reflect those changes back to the calling function. In this case only addresses of the variables are passed to a function so that function can work directly over the addresses.
-Here are two programs to understand the difference: First example is for Pass by value:
-#include <stdio.h>
-/* function declaration goes here.*/
-void swap( int p1, int p2 );
-int main()
-{
-   int a = 10;
-   int b = 20;
-   printf("Before: Value of a = %d and value of b = %d\n", a, b );
-   swap( a, b );
-   printf("After: Value of a = %d and value of b = %d\n", a, b );
-}
-void swap( int p1, int p2 )
-{
-    int t;
-    t = p2;
-    p2 = p1;
-    p1 = t;
-   printf("Value of a (p1) = %d and value of b(p2) = %d\n", p1, p2 );
-}
-Here is the result produced by the above example. Here the values of a and b remain unchanged before calling swap function and after calling swap function.
-Before: Value of a = 10 and value of b = 20
-Value of a (p1) = 20 and value of b(p2) = 10
-After: Value of a = 10 and value of b = 20
-Following is the example which demonstrate the concept of pass by reference
-#include <stdio.h>
-/* function declaration goes here.*/
-void swap( int *p1, int *p2 );
-int main()
-{
-   int a = 10;
-   int b = 20;
-   printf("Before: Value of a = %d and value of b = %d\n", a, b );
-   swap( &a, &b );
-   printf("After: Value of a = %d and value of b = %d\n", a, b );
-}
-void swap( int *p1, int *p2 )
-{
-    int t;
-    t = *p2;
-    *p2 = *p1;
-    *p1 = t;
-   printf("Value of a (p1) = %d and value of b(p2) = %d\n", *p1, *p2 );
-}
-today date 20/3/2016
-name=sahil shete