Home : C language

Summary of the C Language

General form of a C program

/* multi-line comments */

// single-line comments

#include <filename>: Include a "header" file from a "system" directory, e.g. for any standard libraries used.
#include "filename": Include a "header" file from a "local" directory, e.g. for definitions which are global to a project.
#define label value: Define literal constants; the compiler will replace every occurence of label in the source code with the text specified by value.

global variable declarations: These variables are accessible by all functions in the file, and are also "public" (and hence accessible from any other file in the program) unless declared with the static attribute.

int main() {: the first function called when the program executes; returning from it returns to the operating system.
statement;
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statement;
}

return-typefunction-name(parameter variable declarations) {: local variable declarations

statement;
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statement;
}