Listing 11.2. Writing past the end of an array.
1: //Listing 11.2
2: // Demonstrates what happens when you write past the end
3: // of an array
4:
5:  #include <iostream.h>
6: int main()
7: {
8: // sentinels
9: long sentinelOne[3];
10: long TargetArray[25]; // array to fill
11: long sentinelTwo[3];
12: int i;
13: for (i=0; i<3; i++)
14: sentinelOne[i] = sentinelTwo[i] = 0;
15:
16: for (i=0; i<25; i++)
17: TargetArray[i] = 0;
18:
19: cout << "Test 1: \n"; // test current values (should be
0)
20: cout << "TargetArray[0]: " << TargetArray[0] << "\n";
21: cout << "TargetArray[24]: " << TargetArray[24] << "\n\n";
22:
23: for (i = 0; i<3; i++)
24: {
25: cout << "sentinelOne[" << i << "]: ";
26: cout << sentinelOne[i] << "\n";
27: cout << "sentinelTwo[" << i << "]: ";
28: cout << sentinelTwo[i]<< "\n";
29: }
30:
31: cout << "\nAssigning...";
32: for (i = 0; i<=25; i++)
33: TargetArray[i] = 20;
34:
35: cout << "\nTest 2: \n";
36: cout << "TargetArray[0]: " << TargetArray[0] << "\n";
37: cout << "TargetArray[24]: " << TargetArray[24] << "\n";
38: cout << "TargetArray[25]: " << TargetArray[25] << "\n\n";
39: for (i = 0; i<3; i++)
40: {
41: cout << "sentinelOne[" << i << "]: ";
42: cout << sentinelOne[i]<< "\n";
43: cout << "sentinelTwo[" << i << "]: ";
44: cout << sentinelTwo[i]<< "\n";
45: }
46:
47: return 0;
48: }
Output: Test 1:
TargetArray[0]: 0
TargetArray[24]: 0
SentinelOne[0]: 0
SentinelTwo[0]: 0
SentinelOne[1]: 0
SentinelTwo[1]: 0
SentinelOne[2]: 0
SentinelTwo[2]: 0
Assigning...
Test 2:
TargetArray[0]: 20
TargetArray[24]: 20
TargetArray[25]: 20
SentinelOne[0]: 20
SentinelTwo[0]: 0
SentinelOne[1]: 0
SentinelTwo[1]: 0
SentinelOne[2]: 0
SentinelTwo[2]: 0