Homework from Liangzhenwen

Diophantus.c

@@ -0,0 +1,18 @@
+#include <stdio.h>
+int main(int argc, char** argv)
+{
+    int fatherAge=0;
+	for(double i=1.0;i<100;i++)           //�������� 
+	{
+		for(double j=1;j<200;j++)       //�������� 
+		{
+			if((1.0/6.0*j+1.0/12.0*j+1.0/7.0*j+5+i+4==j)&&(2*i==j))
+			{
+				fatherAge=j;
+				break;
+			}
+		}
+	}
+	printf("������ʱ����ͼ����Ϊ%d",FatherAge-4);
+	return 0;
+}

Encrypted.c

@@ -0,0 +1,52 @@
+#include <stdio.h> 
+#include <string.h>
+#include <stdlib.h>
+
+void Encrypte(char* p)
+{
+	int i = 0;
+	while (p[i] != '\0')
+	{
+		p[i] = p[i] + '3' - '1';
+		printf("%c", p[i]);
+		i++;
+	}
+	printf("\n");
+}
+
+void Decrypte(char* p)
+{
+	int i = 0;
+	while (p[i] != '\0')
+	{
+		p[i] = p[i] - '3' + '1';
+		printf("%c", p[i]);
+		i++;
+	}
+	printf("\n");
+}
+
+int main()
+{
+	char p[10000];
+	int Judge = 0;
+	printf("Please input the string need opreating\n");
+	scanf("%s", p);
+	printf("En or De?\nPleaes input 1(En) or 2(De)\n");
+	scanf("%d", &Judge);
+	if (Judge == 1)
+	{
+		Encrypte(p);
+	}
+	else if (Judge == 2)
+	{
+		Decrypte(p);
+	}
+	else
+	{
+		printf("Input Error!");
+		return -1;
+	}
+    return 0;
+}
+

Goldbach.c

@@ -0,0 +1,85 @@
+#include <stdio.h>
+
+/*int pd(int n)
+{
+	for(int i=2;i<=n/2;i++)                    //This program is used for drawing a table
+	{
+		if(n%i==0)
+		return 0;
+	}
+	return 1;
+}
+
+
+int main(int argc, char** argv) 
+{
+	int a[100];
+	int tot=0;
+	printf("a[0]=2\n");
+	for(int i=3;i<100;i++)
+	{
+		if(pd(i))
+		{
+			a[tot++]=i;
+			printf("a[%d]=%d;\n",tot,i);
+		}
+	}
+	return 0;
+}  */
+
+int main()
+{
+	int a[25];        //���
+	int judge = 0;
+	a[0] = 2;
+	a[1] = 3;
+	a[2] = 5;
+	a[3] = 7;
+	a[4] = 11;
+	a[5] = 13;
+	a[6] = 17;
+	a[7] = 19;
+	a[8] = 23;
+	a[9] = 29;
+	a[10] = 31;
+	a[11] = 37;
+	a[12] = 41;
+	a[13] = 43;
+	a[14] = 47;
+	a[15] = 53;
+	a[16] = 59;
+	a[17] = 61;
+	a[18] = 67;
+	a[19] = 71;
+	a[20] = 73;
+	a[21] = 79;
+	a[22] = 83;
+	a[23] = 89;
+	a[24] = 97;
+	for (int i = 4; i <=100; i+=2)
+	{
+		for (int j = 0; j < 25; j++)
+		{
+			for (int k = 0; k < 25; k++)
+			{
+				if (a[j] + a[k] == i)
+				{
+					judge = 1;
+					break;
+				}
+			}
+			if (judge==1)
+			{
+				cout << i << "�����°ͺղ���" << endl;
+				break;
+			}
+			else if (judge==0)
+			{
+				return -1;
+				printf("Goldbach do not exists");
+			}
+		judge = 0;
+	}
+    return 0;
+}
+

Running Letter.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <windows.h>
+
+int main(int argc, char** argv)
+{
+	int i = 0;
+	int j = 0;
+	while (1)
+	{
+		printf("R");
+		Sleep(30);
+		system("cls");
+		int op = 1;
+		for (i = 0; i<79&&i>=0; i+=op)
+		{
+			for (j = 0; j < i; j++)
+			{
+				printf(" ");
+			}
+			printf("R");
+			Sleep(30);
+			system("cls");
+			if (i == 78)
+			{
+				op = -1;
+			}
+			if (i == 0)
+			{
+				op = 1;
+			}
+		}
+	}
+	return 0;
+}