level_1_p01.c to level_1_p06.c

practices/c/level1/p01_runningLetter/level_1_p01.c

@@ -0,0 +1,21 @@
+#include<stdio.h>
+#include<windows.h>
+main()
+{
+	for(int i=1;i<=50;i++){
+		for(int j=1;j<=i;j++){
+			printf(" ");
+		}
+		printf("R");
+		Sleep(10);
+		system("cls");
+	}
+	for(int i=50;i>=1;i--){
+		for(int j=i;j>=1;j--){
+			printf(" ");
+		}
+		printf("R");
+		Sleep(10);
+		system("cls");
+	}
+}

practices/c/level1/p02_isPrime/level_1_p02.c

@@ -0,0 +1,15 @@
+#include<stdio.h>
+main()
+{ 	
+	int a;
+	scanf("%d",&a);
+	if(a==1){
+		printf("非素数");}
+	for(int i=2;i<=a-1;i++){
+		if(a%i==0){
+			printf("非素数");
+			break;}
+		else
+			printf("素数"); 	
+	}
+}

practices/c/level1/p03_Diophantus/level_1_p03.c

@@ -0,0 +1,14 @@
+#include<stdio.h>
+main()
+{
+	int ageDio;int ageSon;
+	int i,j;
+	for(i=1;i<=100;i++)
+	  for(j=1;j<=100;j++){
+		   ageDio=12*i*7*j;
+		   ageSon=ageDio/2;
+		    if(ageSon==((ageDio-4)-(ageDio*11/28+5))){
+		 printf("%d",ageDio);
+		}
+	}
+}

practices/c/level1/p04_ narcissus/level_1_p04.c

@@ -0,0 +1,11 @@
+#include<stdio.h>
+main()
+{
+	int a,b,c,result;int i;
+	for(a=1;a<=9;a++)
+	  for(b=0;b<=9;b++)
+	    for(c=0;c<=9;c++){
+		    if(100*a+10*b+c==a*a*a+b*b*b+c*c*c)
+		    printf("%d\n",100*a+10*b+c);
+	}
+}

practices/c/level1/p05_allPrimes/level_1_p05.c

@@ -0,0 +1,24 @@
+#include<stdio.h>
+#include<math.h>
+#include<time.h>
+int prime(int);
+main()
+{
+	int i,j;
+	for(i=2;i<=1000;i++){
+		if(prime(i)>0)
+		printf("%d\n",i);
+	}
+	printf("\n");
+	printf("%d",(int)clock());
+}
+
+int prime(int m)
+{
+	int k;int i;
+	k=sqrt(m);
+	for (i=2;i<=k;i++)
+		if (m%i==0) break;
+		if (i>k) return m;
+	else return 0;
+}

practices/c/level1/p06_Goldbach/level_1_p06.c

@@ -0,0 +1,33 @@
+#include<stdio.h> 
+#include<math.h> 
+int checkprime(int m)
+{
+	int k;int i;
+	k=sqrt(m);
+	for (i=2;i<=k;i++)
+		if (m%i==0) break;
+		if (i>k) return 1;
+		else return 0;
+}
+
+int main()
+{
+	int a;int prime[100];int b;int c=0;
+
+	for(int i=2;i<=100;i++){
+		b=checkprime(i);
+		if(b==1){
+			prime[c]=i;
+			c++;
+		}
+
+	}
+	for(int i=2;i<=50;i++){
+		for(int j=0;j<=24;j++){
+				a=2*i-prime[j];
+				if(checkprime(a)==1){
+					printf("%d=%d+%d\n",2*i,a,prime[j]);break;
+				}	
+		}
+	}
+}