初识C语言（5）

int main()
{
  int a = 10;
  int b = 20;
  if (a < b)   //注意if后面要加条件语句且条件语句后不能加“；”
    printf("a = %dn ", a);
  else
    printf("b = %dn", b);
  return 0;

}

int main()
{
  int i = 0;              //while函数结构
  while (i < 5)           //while加上条件语句
  {                       //加上大括号
    i++;                  //加上要循环的语句
    printf("%dn", i);
  }
  printf("%dn", i);

  return 0;
}

int S(int a, int b)
{
  int z = a + b;
  return z;
}
int main()
{
  int x = 20;
  int y = 30;
  int sum = S(x, y);
  printf("%dn", sum);

  return 0;
}

int S(int a, int b)
{
  int z = a + b;
  return z;
}
int main()
{
  int x = 20;
  int y = 30;
  int sum = 0;
  sum = S(x,y);
  printf("%dn", sum);
  return 0;
}