Pointer :C/C++ brush up

int a;
&a                                  address of a
int *p                              capable of storing address of a non pointer
int **p                            capable of storing address of a pointer .this is also known as double pointer

Let us consider and code to understand above concept better

1. int *p;
2. int **c;
3. int a[ ]={1,2,3,4};
4. *p=a;                      //*p gives value of a[0] i.e 1                                  
5. **c=&p;                 //c gives value(pointer stores address in its value) of p pointer 2293552
6.                                //**c gives address of p pointer
7.                                //*c --check yourself ! I don't Know
8. printf("%u",p);       //p gives address of a[0] 2293548  
9. *(a+i) is same as a[i]              
10. (a+i) is same as a or &a

Notations for 2-D array

1. //  in 1-d array you write int*p=a; but if a is 2-d array then this statement will give error
2. int b[2][3]={ {1,2,3} , {3,4,2} };  //here b[0] occupy 8 bytes as 2 x {[0],[1],[2],[4]}=2 x 4=8 
3. 
   
4. int(*p)[3]=b;       <--correct statement
5. printf("%d",*b); / printf("%d",b[0]); / printf("%d",&b[0][0]); / printf("%d",b);printf("%d",&b[0]); <--means an address of first element.first row b[0][0]
6. .
7. printf("%d",*(*b+1)); <--means value at b[0][1] which is 2
8. .
9. Concluded: b[i][j]=*(b[i]+j) / *(*(b+i)+j) 
10. .
11. .
12. 
    
13. printf("%d",b+1);/printf("%d",*(b+1));/printf("%d",b[1]);/printf("%d",&b[1][0]);<--means 
14.                                                 //address of first element second row b[1][0]
15. 
    
16. printf("%d",*(b+1)+2);.  //means address of b[1][2]
17. 
    

Notations for 3-D array

1. int c[3][2][2]={     {{2,5},{7,9}}  , {{3,4},{6,1}} , {{0,8},{11,13}}  };
2.  c[i][j][k]
3. printf("%d",*c)  / printf("%d",c[0])  / printf("%d",c[0][0]) <--addr of c[0][0][0]
4. 
   
5.  printf("%d",*(c[1]+1))/ / printf("%d",c[1][1])/ / printf("%d",&c[1][1][0])<--addr of c[1][1][0]
6.                                        printf("%d",*(c[0][1]+1)) <--value of c[0][1][1];
7. i.e c[i][j][k]= / printf("%d",*(c[i][j]+k));/printf("%d",*(*(c[i]+j)+k));/printf("%d",*(*(*(c+i)+j)+k));

Do you Know ?

• loop pointer move by size of data type
• scanf has &a to take value
• printf has just a to print value
• in array no need to write & while passing address

type specifier for printing a address--%u