How to use callback function pointer in cpp/C/C++

Program for callback /function pointer in CPP/C/C++

What is function pointers?As we know a pointer is a special variable that folds the address of another variable.
Function pointer is also  a pointer that hold the address of a function.

Int array[10]; // here array is a constant pointer to a 10 element array. That is constant pointer to first element of array.

Can we declare a non-constant pointer to a function? Yes we can .

Int (*funcPtr)();//funcPtr is a pointer to a function that takes no arguments and returns an integers.//parenthesis is must here as we are not assigning the return type.

Int (*funcPtr)(int,int);//funcPtr is a pointer to a function that takes two arguments and returns an integers.

How to use malloc for 2d array dynamic memory allocation

/*How to use malloc for 2d array dynamic memory allocation. How to write 2-d array with dynamic memory allocation */

#include<stdio.h>

#include<malloc.h>

int main()

{

int r,c,i,j;

printf("Enter No of rows and columns:");

scanf("%d%d",&r,&c);

int **array;

array=(int**)malloc(r*sizeof(int));

for(i=0;i<r;i++)

{

array[i]=malloc(c*sizeof(int));

}

How to use new to allocate memory for 3d array in CPP C++

/*How to use new to allocate memory for 3d array. How to use malloc for 3 dimensional array. CPP program for dynamically allocating memory for 3d array. How to write three dimensional array with malloc with new */

#include<iostream>

using namespace std;

int main()

{

// 3 Dimensions Array

// two 3x4 array

int x = 2, y = 3, z = 4;

int i, j, k;

// memory allocation for 3D

int ***array3D = new int**[x];

for(i = 0; i < x; i++)

{

array3D[i] = new int*[y];

for(j = 0; j < y; j++)

{

array3D[i][j] = new int[z];

}

}

How to learn stack and flow of function call and control in cpp

/*How to learn stack. Stack is memory in which Last in first out is followed.
When function call is encountered the address of the next statement is stored or pushed in the stack. When the control returns back from the definition to calling function the address is poped out which is nothing but the statement next to the function call and executed.*/
#include<stdio.h>
#include<iostream>
using namespace std;
void function1();
void function2();

int main()
{
printf("1\n");
printf("2\n");
function1();
printf("3\n");
printf("4\n");

return 0;
}
void function1()
{
printf("1.1\n");
printf("1.2\n");
function2();
printf("1.3\n");
printf("1.4\n");
}
void function2()
{
printf("2.1\n");
printf("2.2\n");
}

How to learn recursive function call in cpp/C++/C

/*How to learn recursive function call in cpp/C++/C
 Cpp Program to learn recursive function */
#include<iostream>
using namespace std;
int sum(int m, int k);
int main()
{
int i,m,k;
m=3;
k=2;
i=sum(m,k);
cout<<"sum="<<i<<endl;
//return 0;
}
int sum(int rm, int rk)
{
cout<<rm<<" "<<rk<<endl;
if(rm==0) return(rk);//termination condition
else return(1+sum(rk, rm-1));//recursive condition//if not +1 then sum=0
}