Basic Syntax

More Basic

#include<stdio.h> 
int main(void) {
  printf("Hello World");

  return 0;
}

#include<stdio.h>mean is reading library(In C lang it is called header file).
int main(void)is entry point function of programs.
printf()is display to standerd output.

Variable declaration

short sh;
int in = 1;
long lo = in;
float fl = 0.5;
double dou = 0.55;
char = 'a';
bool bo = true;

char array[5] = {'h', 'o', 'g', 'e', '\0'};
char str[] = "piyo";

unsigned int uin = 100;
unsigned float ufl = 0.2;

'\0' mean is line end.

This is part of the variable declaration.

Enum

#include<stdio.h>
// default start is 0
enum Week { Sun, Mon, Tue};

int main(void) {
  enum Week week;
  week = Sun;
  // Can not used other than defined enum value
  // week = Fri; // Error
  printf("%d", week);

  return 0;
}

"for" and "while" loop

#include<stdio.h>
for(int i = 0; i < 5; i++) {
  printf("for loop : %d\n", i);
}

int j = 0;
while(j == 3) {
  j++;
  if(j == 1) continue;
  printf("while loop : %d\n", j);
}

int k = 0;
do {
  k++;
  printf("%d\n", k);
}while(k == 5);

"switch case" and "goto"

#include<stdio.h>
int j = 2
bar:
swtich(j) {
    case 1: break;
    case 2: break;
    case 3: goto foo;
    case 4: goto bar;
    default: break;
}
foo:

Be careful not to become spaghetti code when using 'goto'.

"if" and "if else"

#include<stdio.h>
int i = 0;
if(i == 0) {
  printf("i == 1");
} else if(i == 2) {
  printf("i == 2");
} else {
  printf("Other");
}

Function

#include<stdio.h>

void disphello(void) {
  printf("Hello);
}

int main(void){
  disphello();

  return 0;
}

Frequently used function declaration method

#include<stdio.h>
void disphello(void);

int main(void) {
  disphello();

  return 0;
}

void disphello(void) {
  printf("Hello");
}