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Pointer with function in C
We can use pointers with functions in following ways:
Function returning pointer
In C language, a function can even return a pointer like other data types.
The syntax for function returning a pointer is:
Data_type *fun_name(Arguments);
| Program to demonstrate a function returning pointer |
| #include<stdio.h> int *sum(int a,int b) { int c=a+b; return &c; } int main() { int *s; s=sum(10,14); printf(“\nSum=%d”,*s); return(0); } |
| Output |
| Sum=30 |
| Description |
| In the above program, the function sum() is returning pointer as int *sum(int a,int b).
This function has been called within main() by taking a pointer variable s as int *s and assigning function calling statement to variable s as s=sum(10,14); |
Pointer to function
Function also has an address in memory. This address is used when the function is called.
By storing this address in a function pointer, the function can also be called through this pointer.
Using function pointers, functions are passed as arguments to other functions.
| Program to demonstrate the use of pointer to function. |
| #include<stdio.h>
void fun(int val) fp= &fun; fp(10); return(0); |
| Output |
| Value=10 |
| Description |
| In the above program, the function fun(int val) is defined.
Function pointer has been declared as void (*fp)(int). This pointer looks similar to function definition i.e. void is the return type and int is within parenthesis specifying argument of int type. fp= &fun statement assigns the address of function fun in function ponter fp. fp(10) calls function fun with argument value 2. |