**Course Title:** Mastering C: From Fundamentals to Advanced Programming **Section Title:** Debugging and Testing Techniques **Topic:** Debug and test a provided C program, identifying and fixing issues.(Lab topic) **Introduction** Debugging and testing are crucial steps in the software development process. They help ensure that your program runs correctly, efficiently, and reliably. In this lab, you will be provided with a C program that contains errors and issues. Your task is to debug and test the program, identifying and fixing the problems. **The Program** Here is the provided C program: ```c // calculate_average.c #include <stdio.h> int main() { int scores[] = {90, 80, 70, 60}; int sum = 0; for (int i = 0; i <= 4; i++) { sum += scores[i]; } double average = sum / 4; printf("The average score is: %.2f\n", average); return 0; } ``` This program is supposed to calculate the average score of a set of numbers. However, it contains several errors that prevent it from working correctly. **Task** Your task is to: 1. Compile the program using `gcc` and identify the errors. 2. Use a debugger (such as `gdb`) to step through the program and identify the issues. 3. Fix the errors and modify the program to calculate the average score correctly. **Step 1: Compile and Run the Program** Compile the program using `gcc`: ```bash gcc calculate_average.c -o calculate_average ``` Run the program: ```bash ./calculate_average ``` Note the errors and output. **Step 2: Use a Debugger** Use `gdb` to step through the program: ```bash gdb ./calculate_average ``` Use the `break` command to set a breakpoint at the `main` function: ```gdb (gdb) break main ``` Use the `run` command to start the program: ```gdb (gdb) run ``` Use the `step` command to step through the program: ```gdb (gdb) step ``` Note the values of variables and expressions as you step through the program. **Step 3: Fix the Errors** Based on your observations, fix the errors in the program. Modify the program to calculate the average score correctly. **Solutions** Here are some possible solutions: * Fix the loop condition to `i < 4` instead of `i <= 4`. * Initialize the `sum` variable to 0 before using it. * Use the correct number of elements in the `scores` array when calculating the average. **Modified Program** ```c // calculate_average.c #include <stdio.h> int main() { int scores[] = {90, 80, 70, 60}; int sum = 0; for (int i = 0; i < 4; i++) { sum += scores[i]; } double average = (double) sum / 4; printf("The average score is: %.2f\n", average); return 0; } ``` **Conclusion** In this lab, you have debugged and tested a C program, identifying and fixing issues. You have used a debugger to step through the program and modified the program to calculate the average score correctly. **Additional Resources** * [GDB Documentation](https://www.gnu.org/software/gdb/documentation/) * [Valgrind Documentation](https://valgrind.org/docs/manual/index.html) **Leave a Comment/Ask for Help** If you have any questions or need help with this topic, please leave a comment below. This concludes the lab on debugging and testing a C program. In the next topic, we will cover advanced memory management techniques.