SESSIONS 9(POINTER).md

1). INCREMENT USING POINTERS

    #include <stdio.h>
    int main() 
    {
    int a, b, c;
    scanf("%d%d%d", &a, &b, &c);
    int *ptr[3] = {&a, &b, &c};
    printf("value of a: %d, b: %d, c: %d", *ptr[0], *ptr[1], *ptr[2]);
    *ptr[0] +=10;
    *ptr[1] +=10;
    *ptr[2] +=10;
    printf("\nAfter adding 10\nvalue of a: %d, b: %d, c: %d", *ptr[0], *ptr[1], *ptr[2]);
    return 0;
    }

2)DHONI AND SHANE WATSON

    #include <stdio.h>
    #include <string.h>
    void RevString(char *ptr, int num)
 {
     while (num > 0)
     {
            printf("%c",*ptr);
            ptr--;
            num--;
    }
    return;
    }
    int main()
    {
            int lines;
            scanf("%d", &lines);
            while (lines != 0 ){
            char str[2000];
            scanf("%s", str);
            char * token = strtok(str, ".");
            int len = strlen(token);
            char *ptr = &token[len-1];
            RevString(ptr, len);
            while (token != NULL)
            {
                    token = strtok(NULL, ".");
                    if( token != NULL)
                    {
                            printf(".");
                            len = strlen(token);
                            char *ptr = &token[len-1];
                            RevString(ptr, len); 
                    }
            }
            printf("\n");
            lines -= 1;
    }
    return 0;
  }

3). Change constant value using pointer

         #include <stdio.h>
         int main()
         {
            const int a = 10;
            const int *p;
            p = &a;
            printf("Before changing -constant value of a:%d\n",a);
            scanf("%d",p);
            printf("After changing - value of a:%d\n",a);
            return 0;
         }

4). Interchange num

            #include <stdio.h>
            void interchange (int *num1, int *num2)
            {
                    int temp;
                    temp = *num1;
                    *num1 = *num2;
                    *num2 = temp;
                    printf("%d %d", *num1, *num2);
                    return;
            }

**5). Amelia's Game

            #include <stdio.h>
            int main()
            {
                    int lines;
                    scanf("%d", &lines);
                    if (lines < 0 || lines > 10000)
                    {
                            printf("INVALID INPUT");
                            return 0;
                    }
                    else 
                    {
                             while (lines != 0){
                             int num;
                             scanf("%d", &num);
                             if (num < 0 || num > 100)
                             {
                                    printf("INVALID INPUT");
                                    return 0;
                             }
                             int i, arr[num];
                             int *ptr = &arr[0];
                             for (i=0; i < num; i++)
                             {
                                    scanf("%d", ptr);
                                    if (*ptr % 3 == 0)
                                    {
                                            printf("%d\n", *ptr);
                                    }
                             }
                             lines--;
                     }
                   }
                    return 0;
                 }

6). Internet protocol addressing

        #include <stdio.h>
        #include <string.h>
        #include <stdlib.h>
        #define DELIM "."
        int valid_digit(char *ip_str) 
        {
            while (*ip_str) 
            {
                    if (*ip_str >= '0' && *ip_str <= '9')
                    ++ip_str;
                     else
                    return 0;
            }
            return 1;
        }
        int is_valid_ip(char *ip_str)
         {
            int i, num, dots = 0;
            char *ptr;
            if (ip_str == NULL)
            return 0;
            ptr = strtok(ip_str,DELIM);
            if (ptr == NULL)
            return 0;
            while (ptr) 
            {
             if (!valid_digit(ptr))
             return 0;
             num = atoi(ptr);
             if (num >= 0 && num <= 255) 
             {
                    ptr = strtok(NULL, DELIM);
                    if (ptr != NULL)
                    ++dots;
            }
            else
            return 0;
            }
            if (dots !=3)
            return 0;
            return 1;
          }
            int main()
            {int t,i;
            char ip_str[50];
            //scanf("%s",ip_str);
            scanf("%d",&t);
            LOOP :do
            {
            if ( t != 0 )
            {
                    scanf("%s",ip_str);
                    is_valid_ip(ip_str)? printf("Valid\n"): printf("Not valid\n");
                    t=t-1;
                    goto LOOP;
             }
         }while(t>0);
         return 0;
       }

7). Vijay's House

    #include <stdio.h>
    void rect(int a,int b,int * area,int * perim)
    {}
    int main()
    {
    int x, y, Area, Perimeter;
    int *ptrx = &x ;
    int *ptry = &y;
    scanf("%d %d", ptrx, ptry );
    Area = *ptrx * *ptry;
    Perimeter= 2*(*ptrx + *ptry);
    printf("%d" , Area);
    printf(" %d", Perimeter);
    return 0;
    }

8). Reality show

    #include <stdio.h>
    int main()
    {
    int i, j, a, n, number[30];
    scanf("%d", &n);
    for (i = 0; i < n; ++i)
    scanf("%d", &number[i]);
    for (i = 0; i < n; ++i)
    {for (j = i - 1; j > n; --j)
    {if (number[i] > number[j])
    {a = number[i];
    number[i] = number[j];
    number[j] = a; }}}
    for (i = 0; i < n; ++i)
    printf("%d ", number[i]);                                
    return 0;
    }