Declarations

• Variables
  • Declare each variable on a separate line.
  • Variable names start with lowercase letters.
  • UseCamelCaseForVariable names.
  • Avoid short meaningless names.
  • Private or protected class members are prefixed with 'm'.
  • Single character variable names only on temporary counters.
  • Declare variables until they are needed, a.k.a. avoid C style variable declaration.
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Declarations (Variables)

• Start variable names with lowercase letters.
• Declare each variable on a separate line.
• Avoid short meaningless names.
• Use camel case for multiple word variables.

// Avoid.
int a, b, area_of_rectangle;
char *c, *d;

// Prefer.
int height;
int width;
char *name = nullptr;
char *title = nullptr;
int areaOfRectangle = height * width;

Declarations (Variables)

• Declare variables until they are needed.
• If possible avoid declaring global variables.
• When declaring global variables prefix them with a 'g'.
• If Qt is available use the Q_GLOBAL_STATIC macro.
• Declare global string literals as const char[].

/* Avoid. Might fail because static initialization order is undefined. */
Database db;
QueryProcessor qp(db); 

/* If inevitable and available. Guarantees thread-safe initialization on first use. */
Q_GLOBAL_STATIC(Database, gDb);
Q_GLOBAL_STATIC_WITH_ARGS(QueryProcessor, gQp, gDb);  

// Avoid.
const  string gStrAppName = "Code Convention";

// Prefer.
const char gCharAppName[] = "Code Convention";

int main() 
{
    // Avoid.
    int h, w, area;
    h = 10;
    w = 10;
    a = h * w;

    // Prefer.
    int height = 10;
    int width = 10;
    int area = height * width;

    return 0;
}