Debugging in C++: How to recognize the signs of trouble?

C Common signs of trouble during debugging include unexpected crashes, undefined behavior, logic errors, performance bottlenecks, and memory errors. Taking the findMax() function as an example, by checking the input, logic and using the debugger, we found that maxValue was initialized incorrectly, causing it to always return incorrect results. The problem can be solved after correction.

Debugging in C: Recognizing the Signs of Difficulties

In C development, debugging is a vital process that enables you to Ability to identify and fix problems in code. Knowing the signs of difficult medical conditions can greatly speed up the process.

Common signs of trouble

• Exceptional crash: A program crashes while running, usually throwing an error message.
• Undefined behavior: The program behaves unpredictably, such as a memory leak or a segfault.
• Logic Error: The code technically runs, but does not produce the expected results.
• Performance bottleneck: The program runs extremely slowly, affecting the user experience.
• Memory error: The program uses or releases memory improperly, such as memory access violation.

Practical case

Suppose we have a C function findMax(), whose purpose is to find the maximum value in a given array, but it always returns Wrong results.

#include <iostream>
#include <vector>

using namespace std;

int findMax(const vector<int>& arr) {
  int maxValue = INT_MIN;
  for (auto x : arr) {
    if (x > maxValue)
      maxValue = x;
  }
  return maxValue;
}

int main() {
  vector<int> nums = {1, 3, -2, 5, 0};
  cout << "Maximum value: " << findMax(nums) << endl;
  return 0;
}

Running this code will print Maximum value: -2147483648, which is obviously wrong since there are no negative values ​​in the array.

Debugging process

In order to debug the code, we can follow the following steps:

1. Check the input: Make sure the function receives the correct input, i.e. non-empty array.
2. Check logic: Check whether maxValue is initialized correctly and the comparison is correct.
3. Use the debugger: Step through the code to identify the problem.

Through debugging, we found that maxValue is initialized to INT_MIN, which causes it to always be smaller than any element in the array. Changing initialization to 0 solved the problem.

Conclusion

Knowing the signs of bugs in C is critical to debugging your code quickly and efficiently. By following the steps outlined above, you can quickly narrow down the problem and fix the error.

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