Structure of a C Program

The structure of a C program consists of several key components that facilitate its functionality.

Preprocessor Directives: These lines, beginning with #, are processed before compilation. Common directives include #include for standard input/output.

Function Declarations (Optional): Functions can be declared before their use, which is helpful for organizing code.

Main Function: The entry point of any C program is the main() function. Execution starts here, and it typically returns an integer.

c
int main() {
      // Code
      return 0;
}

 Variable Declarations: Variables are declared to store data, such as int a; or float b;.

Statements and Expressions: This includes operations like assignments, calculations, and input/output commands (e.g., printf, scanf).

Control Structures: These structures, such as if, for, and while, control the flow of the program.

Functions (Optional): Additional functions can be defined to modularize the code.

A simple example might be:

#include   // Preprocessor directive
// Function declaration (optional)
void greet();  
int main() {       // Main function
    int num;      // Variable declaration
    printf("Enter a number: "); // Output statement
    scanf("%d", #);  // Input statement
    if (num > 0) {  // Conditional statement
        printf("You entered a positive number.\n");
    } else if (num < 0>        printf("You entered a negative number.\n");
    } else {
        printf("You entered zero.\n");
    }
    greet(); // Call to another function
    return 0; // Return statement
}
// Function definition
void greet() {
    printf("Hello, welcome to the C programming world!\n");
}