U E D R , A S I H C RSS

새싹교실/2012/AClass/2회차




1.0 1000 .


#include<stdio.h>

int main()
{

int num =0;
int sum =0;
printf("0 1000 :\n");
scanf("%d", &num);

do
{
sum += num %10;
num/=10;

}while(!(num == 0));
printf(" 합 : %d \n",sum);

return 0;
}


2. .

#include <stdio.h>


int main()
{
char replace;

printf(" : ");
scanf("%c",&replace);

if( 97 <= replace && replace <= 129){

printf(" :%c\n", replace-32);
}else if( 65 <=replace && replace <= 90){

printf(" :%c\n", replace+32);
}
return 0;

}


3. .

2 .

if(10>x) printf(" ");.

1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
16 17 18 19 20 21

#include<stdio.h>

int main()
{
int i,j;
int num=1;



for(i=0;i<5;i++){

for(j=0;j<=i;j++){

printf("%d",num);
printf(" ");
num+=1;
}
printf("\n");
}


return 0;



}
4. .

1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
16 17 18 19 20 21

#include<stdio.h>// ..

int main(void)
{
int a;
int b;
int num = 1;
for(a=1;a<6;a++){

for(b=6;b>a;b--){
printf(" ");
}
for(b=1;b<=a;b++){
printf("%d",num);
num+=1;

}
printf("\n");
}


}
5. .( 21 )
//1.3.6.10 .. 6 6 ..


#include<stdio.h>

int main()
{
int i,j;
int num=1;
int a;

int k=0;

printf(" :");
scanf("%d",&a);

//

for(i=0;i

for(j=0;j<=i;j++){

printf("%d",num);
printf(" ");
num+=1;

}
printf("\n");
}

return 0;

}

6. 형태 .

// .

#include<stdio.h>

int main()
{

int i;
int star;
int blank;
int scan;

printf("행 :");
scanf("%d",&scan);


for(i=1;i<=scan;i++)
{
for(blank=scan; blank>i;blank--)
printf(" ");
for(star=1;star<=2*i-1;star++)
printf("*");
printf("\n");

}


}
7. 형태 .

// *..

#include<stdio.h>
int diamond(int a);
int main()
{
int i;
printf("행 -: ");
scanf("%d",&i);
diamond(i);
return 0;


}
int diamond(int a)
{
int i,j;
for(i=0;i<=a/2;i++){
for(j=a/2;j>i;j--){
printf(" ");
}
for(j=0;j<=i;j++){
printf("*");
}
for(j=0;j
printf("*");
}
printf("\n");

}
for(i=0;i
for(j=0;j<=i;j++){
printf(" ");

}
for(j=a/2;j>i;j--){
printf("*");
}
for(j=a/2;j>i+1;j--){
printf("*");

}
printf("\n");
}
return i,j;
}
8. 60 F, 61~70 D, 71~80 C, 81~90 B, 90~ A .

#include <stdio.h>
int main(){
int num;

printf(" : ");
scanf("%d", &num);

switch(num/10){
case 10 :
case 9 :
printf("A\n");
break;
case 8 :
printf("B\n");
break;
case 7 :
printf("C\n");
break;
case 6:
printf("D\n");
break;
default :
printf("F\n");
break;
}

}
9.101200 환하 '함' .(main sum=Sum(); printf("%d",sum); )
#include<stdio.h>

int Sum(int x);
int main()
{
int su;
int sum;
sum=Sum(su);

printf("101 200 합: %d\n",sum);

return 0;
}

int Sum(int x)
{
int sum=0;

for(x=100;x<201;x++)
sum+=x;

return x,sum;

}

10. 해 n! .


#include<stdio.h>


int factorial(int x);
int main()
{
int n;

printf(" :");
scanf("%d",&n);


factorial(n);
printf("%d! = %d\n",n,factorial(n));


return 0;
}
int factorial(int x){

if(x==1)
return 1;

else return
x*factorial(x-1);



}

11.n! for .
#include<stdio.h>

int main()

{

int j;
int a;
int factorial=1;

printf("factorial,input number:");
scanf("%d",&a);

if(a==1)
return 1;

for(j=1;j<=a;j++){
factorial *=j;

}
printf("%d\n",factorial);

return 0;


}

12. 해 110 .
#include<stdio.h>


int self(int x);
int main(){

int result;
int a;

result =self(a);//

printf("%d\n",result);
return 0;
}
int self(int x){

int sum=0;
for(x=1;x<11;x++){
sum=x+sum;
}

return x,sum;
}
13. {7,4,2,9,3,1,2} . 3 .

#include<stdio.h>

int main()
{

int a7= {7,4,2,9,3,1,2};
int i=0;


for(i=0;i<7;i++){
if(ai==3)
printf("3 .");

}
return 0;
}
14. {7,4,2,9,3,1,2} . 1 . (, 7 )

#include<stdio.h>

int main()
{

int a7= {7,4,2,9,3,1,2};
int i=0;
int count=0;

for(i=0;i<7;i++){
count+=1;
if(ai==1){

printf("1 %d .", count);
}
}

}
15. {7,4,2,9,3,1,2} . 2 , .
// if 3 7 .. 한
#include<stdio.h>

int main()
{

int a7= {7,4,2,9,3,1,2};
int i=0;
int count=0;

for(i=0;i<7;i++){
count+=1;
if(ai==2){

printf("2 %d .\n", count);
}
}

}

16. {7,4,2,9,3,1,2} . ()하, .

#include<stdio.h>


void sort(int a[], int n);
void main()
{
int list7={7,4,2,9,3,1,2};
int n=sizeof(list)/sizeof(int);
int i;
sort(list,n);

for(i=0;i<7;i++)
printf("%d\n",listi);

}

void sort(int a[], int n)
{

int i,j,temp;
for(i=0;i
for(j=i+1;j
if(ai>aj){
temp=ai;
ai=aj;
aj=temp;
}

}

}

}






1.2 , , .

- . 편함 ''. 히 표 . 2 '형,, ' . 1 1 2 2 (행)한 .

#include<stdio.h>

int main()
{
static int x23; //2행 3 2
int j,k,sum;

x00 = 1;
x01 = 2;
x02 = 3;
x10 = 4;
x11 = 5;
x12 = 6;


sum=0;
for(j=0;j<2;j++) //행
for(k=0;k<3;k++) // 열
sum=sum+xjk;
printf("2 합=%d\n",sum);

}

2.srand()함 , time() .

- (random number) stdlib.h헤 포함 srand() .rand()함 srand() .
srand stdlib.h 포함 . srand . .
time()함 . 해 time.h 헤 포함. 한 time함 1970 1 1 환하 .

#include<stdio.h>
#include<stdlib.h>
#include<time.h>

int main()
{
int a=0;
printf("rand()함 ,1 random number \n");

srand(time(NULL)); // =

printf("%d\n",rand());

return 0;

}

3.포 , 포 .
-포 . , .포 & * . & . &a a . *p p . & , * . : 형 *포; .

4. , .

- 행해 .

---> int a3, int *ptr =a;
---> a0 == *ptr
a1 == *(ptr+1)
a2 == *(ptr+2)

.(포 * .)

.한 포 . [] .



1. 0 1000 .
/10, %10 .
#include <stdio.h>
int main(){

int num;
int temp1, temp2, temp3;
int sum=0;

printf("0-1000 : ");
scanf("%d", &num);

if(num>=0 && num<=1000)
{
temp1=num/1000;
temp2=num%1000;
sum=temp1;
temp1=temp2/100;
temp3=temp2%100;
sum+=temp1;
temp1=temp3/10;
temp2=temp3%10;
sum+=temp1;
sum+=temp2;
printf("%d\n",sum);
}else printf("0-1000 \n");

return 0;
}//01.c


2. .
#include <stdio.h>
int main(){

char al1,al2 ;
printf(": ");
scanf("%c",&al1);

if(al1>='a' && al1<='z') //소문자일 경우
al2=al1-32; // 32
else if(al1>'A' && al1<='Z') //대문자일 경우
al2=al1+32; // 32

printf("%c\n",al2);

return 0;
}// ! 02.c







3. .
2 .
if(10>x) printf(" ");.
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
16 17 18 19 20 21

#include <stdio.h>
int main(){

int i, j;
int num=1;

for(i=1 ; i<=6 ; i++){
for(j=1 ; j
printf("%3d",num);
num+=1;
}
printf("\n");
}

return 0;
}//03.c


4. .
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
16 17 18 19 20 21

#include <stdio.h>
int main(){

int i, j, k;
int num=1;

for(i=1 ; i<=6 ; i++){
for(j=5 ; j>=i ; j--){
printf(" ");
}
for(k=1 ; k
printf("%3d",num);
num+=1;
}
printf("\n");
}

return 0;
}//04.c
5. .( 21 )
#include <stdio.h>
int main(){

int i, j, n;
int num=1;

scanf("%d",&n);

for(i=1 ; ; i++){
for(j=1 ; j
if(n==num){
printf("%3d",num);
printf("\n");
return 0;
}
printf("%3d",num);
num+=1;
}
printf("\n");
}

return 0;
}//05.c


6. 형태 .
#include <stdio.h>
int main(){

int i, j, k, n;
int num=1;
scanf("%d",&n);

for(i=0;i
for(j=1 ; j
printf(" ");
}
for(k=0 ; k<2*i+1 ; k++){
printf("%3d",num);
num++;
}
printf("\n");
}

return 0;
}


7. 형태 .




8. 60 F, 61~70 D, 71~80 C, 81~90 B, 90~ A .
#include <stdio.h>
int main(){
int num;
printf(" : ");
scanf("%d", &num);

switch((num-1)/10){
case 9 :
printf("A\n");
break;
case 8 :
printf("B\n");
break;
case 7 :
printf("C\n");
break;
case 6 :
printf("D\n");
break;
default :
printf("F\n");
break;
}
}//08.c !



9. 101 200 환하 '함' .
(main sum=Sum(); printf("%d",sum); )
#include <stdio.h>
int Sum(void);
int main(){
int sum;
sum = Sum();
printf("%d\n",sum);
return 0;
}
int Sum(void){
int x=101;
int sum=0;
for(x=101 ; x<=200 ; x++)
sum+=x;

return sum;
}//09.c









10. 해 n! .
#include <stdio.h>

int fac(int);
int main(){
int num;
printf(" : ");
scanf("%d", &num);

printf("%d! = %d\n",num, fac(num));
return 0;
}

int fac(int x){
if(x==1)
return 1;
else
return x*fac(x-1);
}//10.c



11. n! for .
#include <stdio.h>
int main(){

int i, num;
int fac=1;
printf(" : ");
scanf("%d", &num);

for(i=1 ; i<=num ; i++){
fac *= i;
}
printf("%d! = %d\n",num, fac);

return 0;
}//11.c



12. 해 110 .
#include <stdio.h>
int sum(int);
int main(){

printf("1 10 합 : %d\n", sum(10));
return 0;
}

int sum(int x){

if(x>0) return (x+sum(x-1));
else return 0;

}
13. {7,4,2,9,3,1,2} . 3 .
#include <stdio.h>
int main(){

int arr[] = {7,4,2,9,3,1,2};
int i;
int k=0;
for(i=0 ; i<7 ; i++){
if(arri==3) k++;
}
if(k!=0)
printf("3 \n");
else
printf("3 \n");

return 0;
}//13.c


14. {7,4,2,9,3,1,2} . 1 . (, 7 )
#include <stdio.h>
int main(){
int arr[]={7,4,2,9,3,1,2};
int i;
for(i=0 ; i<7 ; i++){
if(arri==1)
printf("%d \n",i+1);
}
return 0;
}//14.c

15. {7,4,2,9,3,1,2} . 2 , .
#include <stdio.h>
int main(){
int i;
int c=0;
int arr[]={7,4,2,9,3,1,2};

for(i=0 ; i<7 ; i++){
if(arri==2) c++;
}
if(c!=0){
printf("2 \n");
for(i=0 ; i<7 ; i++){
if(arri==2) printf("%d \n",i+1);
}
}else printf("2 \n");
return 0;
}//15.c



16. {7,4,2,9,3,1,2} . ()하, .
#include <stdio.h>
int main(){

int arr[]={7,4,2,9,3,1,2};
int temp;
int i,j;

for(i=0 ; i<7 ;i++) printf("%d ",arri);
printf("\n");

for(i=0 ; i<6 ; i++){
for(j=i+1 ; j<7 ; j++){
if(arri>=arrj){
temp=arri;
arri=arrj;
arrj=temp;
}
}
}

for(i=0 ; i<7 ;i++) printf("%d ",arri);
printf("\n");

return 0;
}//16.c




1. 2 , , .
int arrij;
i int형 j .
(i) () , (j) (행) .

#include <stdio.h>
int main(){
int arr33 = {
{1,2,3},
{4,5,6},
{7,8,9},
};
int i,j;
for(i=0 ; i<3 ; i++){
for(j=0 ; j<3 ; j++){
printf("%d ",arrij);
}
printf("\n");
}
return 0;
}
2. srand()함 , time() .
seed .
rand()%a+b : a b
#include <stdio.h>
#include <stdlib.h> //rand함
#include <time.h> //time함

int main(){

srand(time(NULL));
printf("%d\n",rand()%100+1); //1-100

return 0;
}//1_02.c


3. 포 , 포 .
. 4트( 4 )

int *a; //int형 int형 포.
char *b; // char형 char형 포.
double *c; // double형 double형 포.


4. , .
arr , 포 p !

< >
- arr p
- arri *(p+i)
- arri pi
- *arr *p
- *(arr+i) *(p+i)
< >
-
- .
- (array++, array--)


1. 0 1000 .(/10, %10 .)
#include <stdio.h>

int main()
{
int num,a,b,c,d;

printf(" : );
scanf("%d",&num);

if(99
{
a=num/100;
b=num%100;
c=b/10;
d=b%10;
printf("%d %d.\n",num,a+c+d);
}

else if(num<100)
{
a=num/10;
b=num%10;
printf("%d %d.\n",num,a+b);
}

}

2. .
#include<stdio.h>
#include<string.h>


int main()
{
char in50,out50;
int i,len;
int diff='a'-'A';

printf(" : ");
gets(in);

len = strlen(in);
for(i=0;i
{
if(('A'<=ini) && (ini<='Z'))
outi = in i + diff;
else if (('a'<=ini) && (ini<='z'))
outi = ini-diff;
else
outi = ini;
}
outi = '\0';

printf(" : %s \n", out);
}
////
3. .
o 한 2 .
o if(10>x) printf(" ");.
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
16 17 18 19 20 21

4. .
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
16 17 18 19 20 21

5. .( 21 )

6. 형태 .

7. 형태 .

8. 60 F, 61~70 D, 71~80 C, 81~90 B, 90~ A .
#include <stdio.h>
int main()
{
int num;
char grade;

printf("¨¬u O¤A : ");
scanf("%d", &num);

switch(num/10){
case 10 :
printf("A\n");
break;
case 9 :
printf("A\n");
break;
case 8 :
printf("B\n");
break;
case 7 :
printf("C\n");
break;
case 6 :
printf("D\n");
break;
default :
printf("F\n");
break;
}

}

9. 101200 환하 '함' .(main sum=Sum(); printf("%d",sum); )

#include <stdio.h>

int Sum(int n);

int main()
{
int sum;
sum=Sum(200);
printf("101~200¾ioC 합O¨¬ %d\n",Sum);
return 0;
}
int Sum(int n)
{
if(n==101)
return 0;
else
return n+Sum(n-1);
}


10. 해 n! .
#include <stdio.h>

int fact(int n);

int main()
{
int n;

printf(" : ");
scanf("%d",&n);
printf("fact(%d) = %1d. \n",n,fact(n));

}

int fact(int n)
{
if(n==0)
return 1;
else
return n*fact(n-1);
}

11. n! for .
#include <stdio.h>


int main()
{
int n,i;
int fact=1;

printf(" : ");
scanf("%d",&n);

for(i=1;i<=n;i++)
{
fact =i*fact;

}
printf("%d! = %d\n",n,fact);


return 0;
}



12. 해 110 .
.#include <stdio.h>

int hap(int n);

int main()
{
printf("1~10 %d\n",hap(10));
return 0;
}
int hap(int n)
{
if(n==0)
return 0;
else
return n+hap(n-1);
}

13. {7,4,2,9,3,1,2} . 3 .

#include<stdio.h>


int main()
{
int arr[] = {7,4,2,9,3,1,2};
int i;

for(i=0;i<=7;i++ )
{


}
printf("3 .");
}

//////For


14. {7,4,2,9,3,1,2} . 1 . (, 7 )



15. {7,4,2,9,3,1,2} . 2 , .


16. {7,4,2,9,3,1,2} . ()하, .



1. 2 , , .

12;
#include<stdio.h>

int main()
{
int arr33;
int i,j;
int k=1;

for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
arrij=k;
k++;
}
}

printf("arr00¬II arr33 \n");

for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
{
printf("%2d",arrij);
}
printf("\n");
}

}


2. srand()함 , time() .
Void srand(unsigned int SEED);
Rand 함. SEED SEED
: <stdlib.h>

3. 포 , 포 .
, .
형*포 ;
4. , .
***
.
***
1)포 .
2)포 크키 .
3) 4 .
4) .


:3,4,5,6,7,14,15,16

황혜


1. 2 , , .
- .
int a23; // 2행 3 2
2. srand()함 , time() .
-srand함 택하 , rand 함 . srand함 , seed.
3. 포 , 포 .
- 포 ( ) 호화 한
int a;
int *pa; // a
pa=&a; // 포
4. , .
: .
: 포 .


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