Simple Programming Guidelines for C Language

The programming guidelines for C language provide recommendations based on the clarity, simplicity, readability, and maintainability of the code.

1. Indentation and Spaces

Recommendation: Use 4 spaces for indentation. Never use the Tab key, and it is recommended that your editor automatically convert Tabs to 4 spaces. This makes it convenient; for example, you can search for “notepad++ tab to 4 spaces” to see how to set it up.

Everyone uses different editors to write code, and the settings for the Tab key may vary. However, the space key is the same for everyone. Therefore, avoid using the Tab key in your code.

// Good: 4 spaces indentation
int main() {
    if (condition) {
        // code block
    } else {
        // code block
    }
}
// Bad: inconsistent indentation (sometimes spaces, sometimes Tabs, or 2 spaces)
int main() {
  if (condition) {→   // → This is the Tab key, code block
    } else {
        // code block
    }
}

Operators and Spaces:

Put spaces around binary operators.

int sum = a + b;     // Good
if (x > y && y != z) // Good
int sum=a+b;         // Bad

Do not add spaces between unary operators and operands.

i++;     // Good
i ++;    // Bad
*ptr;    // Good
* ptr;   // Bad
&value;  // Good
& value; // Bad

Commas and Semicolons:

// Good
for (i = 0; i < 10; i++) func(a, b, c);
// Bad  for (i=0;i<10;i++)func(a,b,c);

2. Braces {} Style

K&R Style, where the left brace does not start on a new line, is also commonly used in the Linux kernel, which reduces code length and makes it more compact. I personally prefer this style.

Allman Style (also known as BSD style), where the left brace starts on a new line.

// K&R Style (left brace does not start on a new line)
int main() {
    if (condition) {
        // code
    } else {
        // code
    }
}
// Allman Style
int main() {
    if (condition) {
        // code
    } else {
        // code
    }
}

3. Line Length and Line Breaks

Each line of code should ideally not exceed 80 or 120 characters, making it easier to read on different devices and editors.

Long expressions should break at low-priority operators, aligning the new line with the previous line’s expression level.

// Good: Break before the operator, with appropriate indentation
if (very_long_variable_name_1 > very_long_variable_name_2    && another_long_condition     && final_condition) {
    long_function_name(very_long_argument_1,
                        very_long_argument_2,
                       very_long_argument_3);
}
// Or indent like this
result = very_long_variable_name_1 + very_long_variable_name_2         + very_long_variable_name_3;

4. Naming Conventions

Consistency is key! The entire project should use a unified naming style.

Variables and Functions

Snake_case (all lowercase, separated by underscores)

For example:student_count, calculate_average()

// Good
int error_number;
int number_of_completed_connection;

Some common abbreviations:

argument can be abbreviated as arg
buffer can be abbreviated as buff
clock can be abbreviated as clk
command can be abbreviated as cmd
compare can be abbreviated as cmp
configuration can be abbreviated as cfg
device can be abbreviated as dev
error can be abbreviated as err
hexadecimal can be abbreviated as hex
increment can be abbreviated as inc
initialize can be abbreviated as init
maximum can be abbreviated as max
message can be abbreviated as msg
minimum can be abbreviated as min
parameter can be abbreviated as para
previous can be abbreviated as prev
register can be abbreviated as reg
semaphore can be abbreviated as sem
statistic can be abbreviated as stat
synchronize can be abbreviated as sync
temp can be abbreviated as tmp

Macros and Constants

All uppercase snake_case

For example:MAX_SIZE, PI_VALUE

 Type Definitions (struct, enum, typedef)

 Snake_case + suffix For example: student_info_s, color_info_e, student_info_t

 Pointer Variables

 Add * next to the type<code>*, and the variable name should indicate its meaning

 For example:char *filename;

5. Function Writing Standards

 Function names should describe the action the function performs, generally using a verb or a verb + noun structure, and the total length of the function should not exceed 80 lines.

// Good
int calculate_student_score(int student_id,
                             const char *course_name,
                            int exam_weight) {
    // Function body
    int score = 0;
    // ... calculation logic ...
    return score;
}

6. Control Statement Standards

 if-else Statements:

// Good
if (condition) {
    // code
} else if (another_condition) {
    // code  
} else {
    // code
}
// Even if there is only one line of code, it is recommended to use braces
if (condition) {
    do_something();
}
// Bad: Missing braces can lead to errors
if (condition)
    do_something();
    // This line always executes, not within the if's scope
    do_another_thing();

 switch Statements:

switch (variable) {
case VALUE_1:
    // code
    break;
case VALUE_2:
    // code
    break;
default:
    // code
    break;
}

3. Line Length and Line Breaks

4. Naming Conventions

5. Function Writing Standards

Related posts

Leave a Comment Cancel reply