基本數據類型

字符型

char c = 'a';

整數型

int a = 7, b = 8, c;
c = a + b;
c = a - b;

數組

int array[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8 ,9};
char name[10] = "Underwood";

array[0] = 10;
name[0] = 'u';

結構體

struct A {
  int number;
  char name[10];
};

struct A s;
s.number = 10;
s.name[0] = 'a'; 

指針

int a = 0;
int *pa = &a;
*pa = 5;

char name[10];
char *pc = name;
*pc = 'a';
pc += 1;
*pc = 'b';

struct A {
  int number;
  char name[10];
};
struct A s;
struct A *ps = &s;
ps->number = 10;
ps->name[0] = 'a';    

流程控制

分支語句

int age = 18;
if (age >=18)
  printf("An adult\n");
else if (age >= 3)
  printf("A child\n");
else
  printf("A baby");

循環語句

int i, sum = 0;
for (i = 0; i < 10; i++)
  sum += I;

int i = 0, sum = 0;
while (i < 10) {
  sum += i;
  i++;
}

函數

void check_age(int age) {
  if (age >=18)
    printf("An adult\n");
  else if (age >= 3)
    printf("A child\n");
  else
    printf("A baby");
}

check_age(18);