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새싹교실/2012/해보자



2.

  • C C++
  • :
  • : C 통해 .
  • : 화 6 6 30 1 30

3. feedback

  • ZeroPage 4F(ThreeFs + Future Action Plan) feedback .
    • Facts, Feelings, Findings, Future Action Plan. , , , , 획.
    • : " 5 .() .() .() .( 획)"
      • ?
  • feedback .
    • ZeroWiki . 하 .
    • . 학 .

  • ZeroWiki MoniWiki Engine Google Chrome Mozila Firefox, Safari Internet Explorer .

4.1. 1

O
O
O

4.1.1.

  • : Datatype name or Datatype name,name,name,...
  • Data type: . .
  • sizeof(parameter): 환한.
    • sizeof(int) = 4, sizeof(char) = 1, sizeof(short) = 2 etc.
  • overflow: , . !
  • Global variable
    - .
    - .
  • Local variable
    - 포함 ( { }) .
    - .
  • Static variable
    - .
    - .
    - .
  • .
  • ! .

4.1.2.

  1. #define pi 3.141592 , .( )

  2. swap(int num1, int num2)함 . 함 , .

void swap(int num1,int num2);

int main(void){
int num1, num2;
printf(" 2 : ");
scanf("%d %d",&num1,&num2);
printf("num1: %d, num2: %d\n",num1, num2);
swap(num1,num2);
}

void swap(int num1,int num2){
//   
printf("after swap\nnum1: %d, num2: %d\n",num1, num2);
}


: . . .

4.2. 2

O
O

4.2.1.

  • if

if(){

}
-
- ( = 0 , = 0)

  • ?
    - true/false
    - (&&,||,== ) .

  • 1)

#include <stdio.h>

int main(void){
   int num;

   scanf_s("%d",&num);
   if(num%2==0)
      printf("");
   else
      printf("");
   return 0;
}

  • - .
    - . ex) if(x==2&&y==3)
    - parenthesis(호) . ex) if((x==2&&y==3)||z==4)

  • 2)

#include <stdio.h>

int main(void){
   int year;

   scanf_s("%d",&year);
   if((year%4==0&&year%100!=0)||year%400==0)
      printf("");
   else
      printf("");
   return 0;
}

  • if if . (dangling else)

if(){

   if(){
  
   }
}


  • - while:
    - for:
    - do while: 3 .

  • while
    - .
    - . -> break,return

  • continue
    - continue .( )

  • 3) a z

#include <stdio.h>

int main(void){
   char letter = 'a';

   while(letter<='z'){
      printf("%c",letter);
      letter++;
   }
   return 0;
}

  • 4) -1

#include <stdio.h>

int main(void){
   int number;
   int sum = 0;
   int count = 0;

   scanf_s("%d",&number);
   while(number!=-1){
      sum += number;
      count++;
      scanf_s("%d",&number);
   }
   if(sum==0&&count==0)
      printf("0");
   else
      printf("%d",sum/count);
   return 0;
}

  • 5) -1

#include <stdio.h>

int main(void){
   int number;
   int sum = 0;
   int count = 0;

   scanf_s("%d",&number);
   while(number!=-1){
      if(number%2==0){
         sum += number;
         count++;
      }
      else
         scanf_s("%d",&number);
   }
   if(sum==0&&count==0)
      printf("0");
   else
      printf("%d",sum/count);
   return 0;
}

4.3. 3&4


34
O O
O O
O X

4.3.1.

  • for(;;)
    - , , !
    - for while .

  • for : 할 횟 확할

  • while : 할 횟 확하 ( )

  • 1) #

#include <stdio.h>

int main(void){
   int num,i;
   
   scanf("%d",&num);
   for(i=0;i<num;i++)
      printf("#");
   return 0;
}

  • 2) .

   #1 *
   #2 **
   #3 ***
   #4 ****

#include <stdio.h>

int main(void){
   int i,j;

   for(i=0;i<4;i++){
      printf("#%d ",i+1);
      for(j=0;j<i;j++)
         printf("*");
      printf("\n");
   }
}

  • 3) <>


(1)*           (2)****
   **              ***
   ***              **
   ****              *

(3)****        (4)   *
   ***              **
   **              ***
   *              ****

(5)   *        (6)*****
     ***           ***
    *****           *
   *******

(7)   *        (8)*****
     ***           ***
    *****           *
     ***           ***
      *           *****

(9) *   *      (10) *****
    ** **           ** **
    *****           *   *
    ** **           ** **
    *   *           *****

(11) 1       1
      2     2
       3   3
        4 4
         5
        6 6
       7   7
      8     8
     9       9


  • 4) 2 .

#include <stdio.h>

int main(void){
   int num,tmp,count=0;
   int i,j;   

   scanf("%d",&num);
   tmp=num;

   while(tmp>=1){
      tmp/=2;
      count++;
   }
   for(i=0;i<count-1;i++){
      tmp=num;
      if(i==0){
         for(j=0;j<count-2;j++)
            tmp/=2;
         printf("%d%d",tmp/2,tmp%2);
         continue;
      }
      for(j=0;j<count-2-i;j++)
         tmp/=2;
      printf("%d",tmp%2);
   }
   return 0;
}
: for .

4.4. 5


O
O
O

4.4.1.


  • switch : case by case
    - if switch .

  • switch break , case .(if )

  • getch(): stdin . !
  • putch(): . .

1) getch() putch() .
#include <stdio.h>
#include <conio.h>

int main(void){
   char ch;
   ch=getch();

   switch(ch){
      case 'a':
         printf(" a .");
         break;
      case 'b':
         printf(" b .");
         break;
      default:
         printf(" ");
         putch();
         printf(".");
   }
   return 0;
}

  • ? . !
    - : func(int a,int b) a b
    - : 함 형, 환형
    - 함 환형 .
    - void형 환하 .

  • int main()함 return 0 : 0 환하 .
    - void main() !

  • : ' ' .
  • : ' ' .

  • : 함 .
    - printf("%d",add(1,3)); add(1,3) 4 .

  • 2) 2 .

#include <stdio.h>

int mean(int a,int b);

int main(void){
   int num1,num2;

   scanf("%d",&num1);
   scanf("%d",&num2);

   printf("%d",mean(num1,num2));

   return 0;
}

int mean(int a,int b){
   int count=2// count     .      .
   return (a+b)/count;
}

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