C++ error: Failed to allocate array, how to solve it?

When programming in C, allocating arrays is one of the most common operations. But sometimes the array allocation fails for some reasons, causing an error in the program. This article explains the causes and solutions to this error.

1. Error reason

When we declare an array in the program and try to allocate memory, we use statements like "new int[n]". Such a statement causes the operating system to try to allocate memory space for n integers for the array. If you encounter problems during this process, error messages such as

terminate called after throwing an instance of 'std::bad_alloc'
what():  std::bad_alloc

or

Segmentation fault (core dumped)

may appear. The meaning of these error messages is that the operating system was not able to successfully allocate the required memory space for the array, causing the program to terminate incorrectly. There are many reasons for this situation, including:

1. Insufficient computer memory
When creating an array, a continuous space needs to be allocated in the memory. If the computer's memory is already occupied, it may not be possible to allocate enough memory space for the array.

2. The array length is too large
If the array to be created is too large, the memory space that needs to be allocated may exceed the computer memory size limit.

3. Program design issues
There are design problems in the program, such as memory leaks, etc., which cause the computer memory space to be occupied.

2. Solution

To address the causes of the above errors, we can adopt the following solutions:

1. Reduce the array length
When the array length is longer When it is large, you can consider reducing the length of the array and reducing the size of the required memory space, thereby reducing the probability of errors when allocating memory.

2. Optimize program design
Optimizing program design is an important way to prevent memory leaks. Problems such as memory leaks in the program should be avoided as much as possible to ensure that the program's memory usage is efficient.

3. Release unused memory
If there is memory in the program that is not released after use, these memories may have an impact on the memory usage of the program. Therefore, unused memory should be released as much as possible to ensure that the memory space used by the program is sufficient.

4. Use operating system virtual memory
When the computer memory is insufficient, you can use the virtual memory technology provided by the operating system. Virtual memory can use the computer's hard disk as a memory expansion, thereby increasing the available memory space and solving the problem of insufficient memory.

5. Avoid algorithms that excessively consume memory
When designing algorithms, algorithms that excessively consume memory should be avoided as much as possible. For example, if loops can be used, avoid using recursive algorithms because recursive algorithms may consume large amounts of memory.

3. Conclusion

No matter when, it is a headache to be unable to allocate memory for an array. However, there are several strategies we can adopt to avoid this happening as much as possible. At the same time, during program design, the impact of memory leaks and other problems on the program should be minimized to improve the memory usage efficiency of the program.

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