Compilation and Debugging Process in C++
The C++ programming language involves several steps and processes, from program creation to program compilation and running. Especially when using C++ programs in compilation and debugging mode. All these stages are essential for converting high-level C++ program code into equivalent machine code, so that the operating system installed on your computer can easily run and execute these programs. The compilation and debugging process is also necessary to fix any errors, mistakes, or bugs in C++ programs.
Here is a detailed breakdown of the compilation and debugging process in C++ programming.
Compilation Process in C++.
The C++ program code compilation process follows several steps and wizards, and these are the main stages of a typical C++ program code compilation task.
Step 1: Preprocessing phase.
The preprocessor processes C++ source code in a header file or pre-processor directive before compiling it. During this preprocessing phase, #define expands the macro value defined in the program defined in the header file or directive.
In C++ program source code, header files, such as #include <iostream>, pre-include all necessary program runtime instructions.
In C++ program source code conditional compilation, key directives such as #ifdef, #ifndef, etc., are evaluated or included for essential tasks.
User comments are then removed during the C++ program source code compilation process.
After this process, you have a modified C++ program source code file, ready to use for compilation in an existing C++ program.
Example.
#include <iostream> // This indicates a preprocessor directive header file, replacing it with the contents of the iostream header.
#define MAX 33 // This is a user-defined custom preprocessor directive header file, where the preprocessor defines MAX as 33.
Step 2: Compilation Phase.
After preprocessing the header or directive, the compiler translates the C++ program source code into assembly code or intermediate code one at a time.
In the program compilation phase.
In this phase, the syntax of the C++ program source code you wrote is checked in detail to ensure that the program source code is valid and follows the specific rules and standards of the C++ language.
The C++ compiler creates a symbol table to keep track of declared variables, functions, and other identifiers in the current program.
It applies optimizations such as inlining, constant folding, and dead code elimination to your program as needed.
The program’s output is an object file. Objects are appended with either a .o or .obj extension, depending on the platform.
Compilation Phase Example.
g++ -c first.cpp # creates an object file as first.o.
The system-created object file contains machine-specific instruction definitions but has not yet been linked into an executable file.
Step 3: Assembly Phase.
In the assembly phase, the assembler (a built-in program in C++ that converts assembly language code) accepts the program source code generated by the C++ compiler and converts it into machine code, creating an object file.
This system-created object file contains all the machine-readable instructions. However, it does not yet constitute a complete executable code, as it may still point to undefined functions, variables, or libraries in the program.
Step 4: Linking Phase.
Here, the program linker accepts one or more C++ program object files generated by the compiler as input and combines and groups them into a single executable. The linker performs several essential tasks in a C++ program, such as:
Resolving external file references; for example, it resolves calls to functions defined in other program files or libraries.
The program bundles or groups the generated object files, libraries, and resources into a unified executable C++ program file, such as a.out, first.exe.
Easily handles and manages symbol resolution by matching function calls and variable references defined in C++ to their actual definitions.
If necessary, the C++ program links them together in libraries, such as the standard library or external libraries.
If a C++ program contains any unresolved reference types, such as calling a user-defined data type function that is defined in the program library but not included in it, a linker error will be displayed.
Linking Phase Example.
g++ first.o -o first # This links the object files and creates an executable file.
In this step, if your system does not display any errors. So, the final executable file first or first.exe is ready to use for execution.
Debugging Process in C++.
The debugging process in C++ programming is the process of finding and resolving errors or bugs in your program. C++ program errors can develop at different stages, including compilation syntax errors, runtime errors such as logical or runtime errors, and linking error correction steps. The debugging process in C++ programming can be divided into several phases.
Step 1: Syntax Errors and Compilation Errors.
Syntax errors appear during the C++ program compilation phase. They develop due to incorrect language constructs, such as a missing semicolon operator, mismatched curly braces, incorrect directives, using and calling the wrong data type, or defining or calling an undeclared variable, etc.
The compiler installed on your computer then outputs an error message that indicates the source code line in the current program where the error occurred, which helps C++ program developers easily correct programming problems.
Example of a syntax error in a C++ program.
#include <iostream>
int main() {
std::cout << “Hi Vcanhelpsu, Let’s try c++” // Here we forgot to write the semicolon operator
return 0;
}
It displays a compiler-time error.
error: expected ‘;’ before ‘return’
