Skip to main content

Pointers and 2-Dimensional arrays in C programming

By
            Multi-dimensional array can also be represented with an equivalent pointer notation as in single dimensional array. A two dimensional array is actually a collection of one dimensional arrays. Therefore we can define a two dimensional array as a pointer to a group of contiguous one-dimensional arrays. Its general syntax is as
  Data_type (*ptr_variable)[expression2];
            Instead of
         Data_type array[expression1][expression2];
   

   Example:
   Suppose x is a two dimensional integer array having 4 rows and 5 columns. We can declare x as
int (*x)[5];
   rather than
int x[4][5];
                    Here, in first declaration, x is defined to be a pointer to a group of contiguous one dimensional 5-element integer arrays. The x points to the first 5-element array, which is actually first row of the two dimensional array. Similarly, x+1 points to the second 5-element array, which is the second row of the two dimensional array. It is illustrated as

An example:

 void main()
     {
  int p[2][3]={   {1,2,3},
                           {4,5,6}
                          };
   clrscr();
   printf("p=%u\tp+1=%u",p,p+1);
   printf("\n*p=%u\t*(p+1)=%u",*p,*(p+1));
   printf("\n*(p+0)+1=%u\t*(p+1)+1=%u",*(p+0)+1,*(p+1)+1);
   printf("\n*(*(p+0)+1)=%u\t*(*(p+1)+1)=%u",*(*(p+0)+1),*(*(p+1)+1));
   getch();
    }

Output:
p=65514                 p+1=65520
*p=65514               *(p+1)=65520
*(p+0)+1=65516    *(p+1)+1=65522
*(*(p+0)+1)=2        *(*(p+1)+1)=5

    It can be illustrated as



Example:
         Write a program to add two 2*3 matrixes using pointer.

void main()
 {
     int (*a)[3],(*b)[3],*(sum)[3],i,j;
     clrscr();
     printf("Enter first matrix:\n");
     for(i=0;i<2;i++)
            for(j=0;j<3;j++)
               scanf("%d",*(a+i)+j);

      printf("Enter second Matrix:\n");
     for(i=0;i<2;i++)
            for(j=0;j<3;j++)
               scanf("%d",*(b+i)+j);

    printf("\nThe sum matrix is:\n");
     for(i=0;i<2;i++)
       {
            for(j=0;j<3;j++)
              {
*(x+2)+1)
 
               *(*(sum+i)+j)= *(*(a+i)+j)+ *(*(b+i)+j);
               printf("\t%d",*(*(sum+i)+j));

              }
       printf("\n");
      }
     getch();

 }  
Labels:

Comments

Post a Comment

Popular posts from this blog

Passing arrays to functions in C programming

By
Like any other variables, we can also pass entire array to a function. An array name can be named as an argument for the prototype declaration and in function header. When we call the function no need to subscript or square brackets. When we pass array that pass as a call by reference because the array name is address for that array. /* Program to illustrate passing array to function */ #include<stdio.h> void display(int) ; /* function prototype */ main( ) { int num[5] = {100, 20, 40, 15, 33, i ; clrscr( ) ; printf (“\n The content of array is \n”) ; for (i=0; i<5; i++) display (num[i]) ; /*Pass array element fo fun */ getch{ } ; } void display(int n) { printf (“\t%d”, n ) ; } Output:     The content of array is 100      20       40       15 3 /* Program to read 10 numbers from keyboard to store these num into array and then c...
Post a Comment
Read more

CPU (Central Processing Unit)

By
PGA reffered as pin grid array in which pins of CPU are lined up in a straight format. SPGA referred as staggered pin grid array. in which pins of CPU are arranged staggered format. LGA reffered to as Land Grid Array in which pins are available within inside the socket but not in the CPU in other words in line grid array, in CPU ther are no pinsbut insteadpins areattached with in a socket which contact with with the CPU. for e.g. LGA775 socket(no pins on cpu) has better cooling system. better contact and better locking(climbing). LGA1155: Letest generation I socket, also reffered as sandy bridge, Turbo boost overclocking. More resent than LGA 1156 socket. LGA1156: ability to north bridge Doul channel DDR3 optional integreted graphics PCI express LGA1366: hi end core i series socket integreted tiple channal memmory controller external control bridge(HUB) Upgrading CPU: need to check its core suppert check multiprocessor supports or not check on the ...
Post a Comment
Read more

Recursive Function in C programming

By
             If a statement within the body of a function calls the same function, the function is called recursive function. Actually, recursion is a process by which a function calls itself repeatedly until some specified condition has been satisfied. This process is used for repetitive computations in which each action is stated in term of previous result. Many iterative or repetitive problems can be written in this form.                To solve a problem using recursive method, two conditions must be satisfied. They are: 1)       Problem could be written or defined in term of its previous result. 2)       Problem statement must include a stopping condition. /*   An example of recursive function to calculate factorial of a number.*/    #include<stdio.h>    #include<conio.h...
Post a Comment
Read more