1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
|
/* cpintarray.c -- Example showing how addresses and arrays are alike
*/
#include <stdio.h>
#define SIZE 8
void cpIntArray(int *a, int *b, int n)
/*It copies n integers starting at b into a*/
{
for(;n>0;n--)
*a++=*b++;
}
void printIntArray(int a[], int n)
/* n is the number of elements in the array a.
* These values are printed out, five per line. */
{
int i;
for (i=0; i<n; ){
printf("\t%d ", a[i++]);
if (i%5==0)
printf("\n");
}
printf("\n");
}
int getIntArray(int a[], int nmax, int sentinel)
/* It reads up to nmax integers and stores then in a; sentinel
* terminates input. */
{
int n = 0;
int temp;
do {
printf("Enter integer [%d to terminate] : ", sentinel);
scanf("%d", &temp);
if (temp==sentinel) break;
if (n==nmax)
printf("array is full\n");
else
a[n++] = temp;
}while (1);
return n;
}
int main(void){
int x[SIZE], nx;
int y[SIZE], ny;
printf("Read the x array:\n");
nx = getIntArray(x,SIZE,0);
printf("The x array is:\n");
printIntArray(x,nx);
printf("Read the y array:\n");
ny = getIntArray(y,SIZE,0);
printf("The y array is:\n");
printIntArray(y,ny);
cpIntArray(x+2,y+3,4);
/*Notice the expression 'x+2'. x is interpreted as the address for
the beginning of the x array. +2 sais to increment that address
by two units, in accordance with the type of x, which is
an integer array. Thus we move from x to two integer locations
past it, that is to the location of x[2]. The same reasoning applied
to 'y+3'.
*/
printf("Printing x after having copied 4 elements\n"
"from y starting at y[3] into x starting at x[2]\n");
printIntArray(x,nx);
}
/* Here is the interaction in a run of this program:
Read the x array:
Enter integer [0 to terminate] : 1
Enter integer [0 to terminate] : 3
Enter integer [0 to terminate] : 5
Enter integer [0 to terminate] : 7
Enter integer [0 to terminate] : 9
Enter integer [0 to terminate] : 11
Enter integer [0 to terminate] : 13
Enter integer [0 to terminate] : 15
Enter integer [0 to terminate] : 0
The x array is:
1 3 5 7 9
11 13 15
Read the y array:
Enter integer [0 to terminate] : 2
Enter integer [0 to terminate] : 4
Enter integer [0 to terminate] : 6
Enter integer [0 to terminate] : 8
Enter integer [0 to terminate] : 10
Enter integer [0 to terminate] : 12
Enter integer [0 to terminate] : 14
Enter integer [0 to terminate] : 16
Enter integer [0 to terminate] : 0
The y array is:
2 4 6 8 10
12 14 16
Printing x after having copied 4 elements
from y starting at y[3] into x starting at x[2]
1 3 8 10 12
14 13 15
*/
|
