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6.6 Exercises

1. What is the output of the following code?

   int x, y, z, w;
        int * pa, * pb, * pc, * pd;
   
        x = 10; y = 20; z = 30;
        pa = &x;
        pb = &y;
   
        printf("%d, %d, %d\n", *pa, *pb, *pc);
        pc = pb;
        printf("%d, %d, %d\n", *pa, *pb, *pc);
        pb = pa;
        printf("%d, %d, %d\n", *pa, *pb, *pc);
        pa = &z;
        printf("%d, %d, %d\n", *pa, *pb, *pc);
        *pa = *pb;
        printf("%d, %d, %d\n", *pa, *pb, *pc);

   What is the output for each of the following programs:

2. #define SWAP(x, y)  {int temp; temp = x; x = y; y = temp; )
        main()
        {    int data1 = 10, data2= 20;
             SWAP(data1, data2);
             printf("Data1 = %d, data2 = %d\n", data1, data2);
        }

3. #define SWAP(x, y)  {int *temp; temp = x; x = y; y = temp; )
        main()
        {    int data1 = 10, data2= 20;
             int *p1, *p2;
             p1 = &data1; p2 = &data2;
             SWAP(p1, p2);
             printf("*p1 = %d, *p2 = %d\n", *p1, *p2);
        }

   Correct the code in the following problems:

4. main()
        {    int x, *p;
   
             x = 13;
             ind_square(*p);
        }
   
        ind_square(int *p)
        {
             *p = *p * *p;
        }

5. main()
        {    int x, *p;
   
             x = 13; p = &x;
             ind_square(&p);
        }
   
        ind_square(int &p)
        {
             *p = *p * *p;
        }

6. main()
        {    int x, *p;
   
             x = 13;
             ind_square(x);
        }
   
        ind_square(int *p)
        {
             *p = *p * *p;
        }

7. main()
        {    int x, *p;
   
             x = 13;
             ind_square(p);
        }
   
        ind_square(int *p)
        {
             *p = *p * *p;
        }