The abnormal behavior of C++ programs often results in program crashes. You may have faced several issues, such as Segmentation fault, Terminated, Floating point exception, and many others. The sample programs below could help you understand the causes of a C++ application crash.
1. Exceptions
Exceptions in C++ are a program's states when it meets an abnormal state. The application will crash if such exceptions are not handled appropriately using try-catch blocks. The following program crashes as a result of a divide-by-zero exception.
Example:
Let us take an example to illustrate the exceptions in C++.
#include <iostream>
int main(){
int number1=10;
int number2=0;
int quo=number1/number2;
printf("\n The Quotient value is: %d",quo);
return 0;
}
Output:
Floating point exception
2. Overflow of a Buffer
A buffer is a place for temporary storage. When a program writes data to a buffer that is larger than the buffer's capacity, the additional data overflows over the buffer's boundary. Data is overwritten in nearby memory regions. When the size of variable num is exceeded, the following program changes its behavior.
Example:
Let us take an example to illustrate the overflow of a Buffer in C++.
#include <iostream>
#include <string.h>
int main(){
int number=100;
std::cout<<"\nThe Value of the number is:"<<number;
char ch[2];
strcpy(ch,"abcdefghghsjksoiwso");
std::cout<<"\nThe Value for the char array is:"<<ch;
return 0;
}
Output:
The Value of the number is: 100
Segmentation fault
3. Stack Overflow
Stack Overflow happens when the call stack pointer overflows the stack bound. The stack has a certain quantity of space. When a program consumes more stack space than is available, the stack is called overflow , and the program crashes. The most common reason is infinite recursion.
The following programs contain an endless number of calls to the function factorial. In this case, the return statement needs to be corrected.
Example:
Let us take an example to illustrate the Stack Overflow in C++.
#include <iostream>
#include <string.h>
// function to find factorial
int fact(int number){
if(number==0)
return 1;
else
return(factorial(number));
}
int main(){
int num=10;
int f=fact(num);
std::cout<<f;
}
Output:
/tmp/HLCeqXFKsW.cpp:9:14: error: 'factorial' was not declared in this scope
9 | return(factorial(number));
| ^~~~~~~~~
4. Segmentation Fault
In C or C++, a segmentation fault occurs when a program attempts to use a memory region that it does not have authorization to access. This error, which is a form of generic protection fault, occurs when memory access is violated. The term "segfaults" refers to segmentation faults.
Example:
Let us take an example to illustrate the Segmentation Fault in C++.
#include <iostream>
int main(){
char *strs;
char names[]="iosttream";
strs=names;
while(1)
(*strs++)='m';
}
Output:
Segmentation fault (core dumped)
5. Memory Leaks
Memory leaking occurs in C++ when developers allocate memory with the new keyword but fail to deallocate the memory with the delete method or delete operator. One of the most common causes of memory leakage in C++ is the incorrect use of the delete operators.
The delete operation should be used to remove a single assigned memory space. However, the delete operator must be used to free an array of data values.
Memory leaking has the following drawbacks:
- If the application contains memory leaks, its memory use rises satirically because all systems have limited storage, and memory is expensive. As a result, it will cause complications.
Example:
Let us take an example to illustrate the Memory Leaks in C++.
#include <iostream>
int main(){
int *nodes;
nodes = (int *) malloc(99999999);
// free(nodes);
}
Debugging tools:
Some debugging tools that used in C++ are as follows:
- Tools: Use debugging tools such as GDB, Valgrind, or AddressSanitizer to find memory problems, leaks, and undefined behavior.
- Code Reviews: In order to identify any problems and make sure best practices are followed, thoroughly review the code.
- Testing: Use extensive testing approaches, such as unit and integration tests, to detect and fix issues at the beginning of the development cycle.
- Best Practices: Use best practices for controlling memory, such as smart references ( std::uniqueptr, std::sharedptr ), RAII (Resources Acquisition Is Initialization), and avoiding raw pointers wherever feasible.
- Static Analysis: Use static analysis techniques to identify potential problems and weaknesses in the codebase.