To start programming in C, you need two essential tools installed on your computer:

1. Text Editor

A text editor is where you write your C source code. Common text editors include:

• Windows: Notepad++, Visual Studio Code (VS Code), Sublime Text
• Linux/macOS: vim, nano, VS Code, gedit
• Cross-platform: VS Code, Atom, Sublime Text

The files you create are called source files and should have the .c extension (for example, program.c).

2. C Compiler

The computer cannot understand your C code directly. A compiler translates your human-readable source code into machine language (binary code) that the computer can execute. The most common free C compiler is GCC (GNU Compiler Collection).

On Windows, you can install MinGW-w64 to get GCC. After installation, you must add the compiler's folder to your system's PATH environment variable so that you can run it from any folder using the command prompt.

To verify your compiler is installed correctly, open Command Prompt and type:

gcc --version

If installed properly, this command will display the GCC version number.

A C program has a specific structure. Every program must have a main() function where execution begins. Here is a simple example that prints a greeting:

#include <stdio.h>

int main() {
    printf("Habari, Tanzania!\n");
    return 0;
}

Explanation of the code:

• #include <stdio.h> — tells the compiler to include the standard input/output library
• int main() — the main function where the program starts
• printf("Habari, Tanzania!\n"); — prints text to the screen; \n creates a new line
• return 0; — tells the operating system the program finished successfully

To write this program:

1. Open your text editor (like Notepad++ or VS Code)
2. Type the code exactly as shown above
3. Save the file as habari.c in a folder you can easily find

After writing the code, you must compile it to create an executable program. Compilation checks your code for errors and translates it into machine language.

Steps to compile:

1. Open Command Prompt (Windows) or Terminal (Linux/macOS)
2. Navigate to the folder where you saved your file using the cd command
3. Type the following command to compile:

gcc habari.c -o habari

This command tells GCC to:

• Take habari.c as input
• Create an executable file named habari (or habari.exe on Windows)

If your code has no errors, the compilation will succeed and create the executable file. If there are errors, the compiler will display error messages showing what is wrong and on which line.

After successful compilation, you can run your program:

On Windows:

habari.exe

On Linux/macOS:

./habari

The output will display:

Habari, Tanzania!

When writing programs, you will encounter errors. There are three main types:

1. Syntax Errors

These occur when you break the rules of C, such as forgetting a semicolon or misspelling a keyword.

Example of syntax error:

#include <stdio.h>
int main() {
    printf("Hello World\n")  // Missing semicolon
    return 0;
}

Error message: expected ';' before 'return'

Fix: Add a semicolon at the end of the printf line.

2. Logical Errors

These occur when your program runs but gives wrong results due to incorrect logic.

Example:

int a = 5, b = 2;
int result = a - b;  // You wanted addition but wrote subtraction

Fix: Change the operator to + if you want to add.

3. Runtime Errors

These occur while the program is running, such as dividing by zero.

Example:

int a = 5, b = 0;
int result = a / b;  // Division by zero causes crash

Fix: Check if the divisor is zero before dividing.

When your program does not work correctly, use these simple debugging methods:

1. Read error messages carefully — The compiler usually tells you where the error is and what type of error it is.

2. Use print statements — Add printf() statements to check if variables have the values you expect at different points in your program.

3. Check your code line by line — Compare your code with working examples from the textbook.

The programming workflow follows these steps:

1. Write your C code in a text editor and save it with .c extension
2. Compile the program using the gcc command
3. Run the compiled executable to see the output
4. Debug any errors that appear by reading error messages and fixing the code
5. Repeat the process until your program works correctly

In Tanzania, programming tools are used in many everyday situations. For example, a small shop owner in Dar es Salaam could use a simple C program to calculate the total price of items, apply discounts, and generate a receipt. By writing and running this program on their computer, they can quickly process customer orders and avoid calculation mistakes when adding up prices in Tanzanian shillings.