Homework

level1/p01_runningLetter/runningLetter.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+
+void main() {
+    int n = 0;
+    const int RIGHT_BORDER = 105, LEFT_BORDER = 0;
+    char value = 1;
+    while (1) {
+        if (value) {
+            for (int i = 0; i < n; i++) {
+                printf(" ");
+            }
+            printf("Running Word");
+            n++;
+            system("cls");
+            if (n == RIGHT_BORDER) {
+                value = 0;
+            }
+        }
+        else {
+            for (int i = 0; i < n; i++) {
+                printf(" ");
+            }
+            printf("Running Word");
+            n--;
+            system("cls");
+            if (n == LEFT_BORDER) {
+                value = 1;
+            }
+        }
+    }
+}
+

level1/p02_isPrime/isprime.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <math.h>
+
+int is_prime(int n){
+	int i;
+	for(i=2;i<=sqrt(n);i++){
+		if(n%i==0){
+			return 0;
+		}	
+	}
+	return 1;
+} 
+
+int main(){
+	int n;
+	printf("Please enter a number: ");
+	scanf("%d",&n);
+	if(is_prime(n)&&n>1){
+		printf("It is a prime number.");
+	}else{
+		printf("It isn't a prime number.'");
+	}
+}

level1/p03_Diophantus/Diophantus.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+//丢番图问题
+int main(){
+	float x;
+	for(x=1;x<200;x++){
+		if((x/6+x/12+x/7+5+x/2+4)==x){
+			printf("%.0f",x);
+			break;
+		}
+	}
+	return 0;
+} 

level1/p04_ narcissus/narcissus.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int main(){
+	int n;
+	int a,b,c;
+	for(n=100;n<1000;n++){
+		c = n%10;//���
+		b = n/10%10;//ʮλ��
+		a = n/100;//���
+		if((a*a*a+b*b*b+c*c*c)==n){
+			printf("%d\n",n);
+		}
+	}
+}

level1/p05_allPrimes/allPrimes.c

@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <math.h>
+#include <time.h>
+
+//�������� 
+int is_prime1(){
+	int i,n,m,t = 0;
+	for(n = 2;n < 1000;n ++){
+		m = 1;
+		for(i = 2;i <= sqrt(n);i ++){
+			if(n % i == 0){
+				m = 0;
+				break;
+			}
+		}
+		if(m == 1){
+			printf("%d\t",n);
+			t ++;
+		}
+		if(t == 15){
+			printf("\n");
+			t = 0;
+		}
+	}
+	return 0;
+}
+
+//����ɸ 
+int is_prime2(){
+	char a[1000] = {1};
+	int i,x,m = 0;
+	for(i = 2;i < 1000;i ++){
+		if(a[i] == 0){
+			for(x = i*i;x < 1000;x = x + i)a[x] = 1;
+			printf("%d\t",i);
+			m ++;
+			if(m == 15){
+				printf("\n");
+				m = 0;
+			}
+		}
+	}
+}
+
+int main(){
+	int n,m = 0;
+	clock_t start_t,end_t;
+	double total_t;
+
+	//�������� 
+	start_t = clock();
+	is_prime1();
+	end_t=clock();
+	total_t = (double)(end_t - start_t) / CLOCKS_PER_SEC;
+	printf("\n�������е���ʱ��Ϊ: %fs\n",total_t);
+
+	//����ɸ 
+	start_t = clock();
+	is_prime2();
+	end_t = clock();
+	total_t = (double)(end_t - start_t) / CLOCKS_PER_SEC;
+	printf("\n�������е���ʱ��Ϊ: %fs",total_t);
+	return 0;
+}

level1/p06_Goldbach/Goldbach.c

@@ -0,0 +1,26 @@
+#include <stdio.h>
+#include <math.h>
+#include <stdbool.h>
+
+bool is_prime(int n){
+	int i;
+	for(i=2;i<=sqrt(n);i++){
+		if(n%i==0)return false;
+	}
+	return true;
+}
+
+int main(){
+	int n,m,x=0;
+	for(n = 4;n <= 100;n += 2){
+		for(m = 2;m <= n;m ++){
+			if(is_prime(m) && is_prime(n - m)){
+				printf("%3d = %2d + %2d\n",n,m,n - m);
+				x++;
+				break;
+			}
+		}
+		if(x==49)printf("The Goldbach is true");
+	}
+	return 0;
+}

level1/p07_encrypt_decrypt/encrypt.c

@@ -0,0 +1,99 @@
+/*���Կ������������*/
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+//����
+void encode(char str[], int n) {
+    int i;
+    char c;
+    for (i = 0; i < strlen(str); ++i) {
+        c = str[i];
+        if (str[i] >= 'A' && str[i] <= 'Z') {
+            if (c + n % 26 <= 'Z') {
+                str[i] = (char)(c + n % 26);
+            }
+            else {
+                str[i] = (char)(c + n % 26 - 26);
+            }
+        }
+        else if (str[i] >= 'a' && str[i] <= 'z') {
+            if (c + n % 26 <= 'z') {
+                str[i] = (char)c + n % 26;
+            }
+            else {
+                str[i] = (char)c + n % 26 - 26;
+            }
+        }
+        else {
+            str[i] = c;//������ĸ��������
+        }
+    }
+    printf("\nAfter encode: \n");
+    puts(str);
+}
+
+//����
+void decode(char str[], int n) {
+    int i;
+    char c;
+    for (i = 0; i <= strlen(str); ++i) {
+        c = str[i];
+        if (str[i] <= 'z' && str[i] >= 'a') {
+            if (c - n % 26 > 'a') {
+                str[i] = (char)(c - n % 26);
+            }
+            else {
+                str[i] = (char)(c - n % 26 + 26);
+            }
+        }
+        else if (str[i] <= 'Z' && str[i] >= 'A') {
+            if (c - n % 26 > 'A') {
+                str[i] = (char)(c - n % 26);
+            }
+            else {
+                str[i] = (char)(c - n % 26 + 26);
+            }
+        }
+        else {
+            str[i] = c;
+        }
+    }
+    printf("\nAfter decode: \n");
+    puts(str);
+}
+
+
+int main() {
+    char str[50];
+    int k, q = 1;
+    int n,c;
+    while (q) {
+        system("cls");
+        printf("Please enter your word:\n");
+        scanf_s("%s", str,50);
+        printf("Please set the encode function: \n");
+        scanf_s("%d", &n);
+        printf("-----------------\n");
+        printf("1: Encryption\n");
+        printf("2: Decryption\n");
+        printf("-----------------\n");
+        printf("\nPlease choose: ");
+        scanf_s("%d", &k);
+        if (k == 1) {
+            encode(str, n);
+        }
+        else if (k == 2) {
+            decode(str, n);
+        }
+
+        printf("Do you want to quit (1/0): \n");
+        scanf_s("%d", &c);
+        if (c == 1) {
+            q = 0;
+        }
+    }
+    return 0;
+
+}
+

level1/p08_hanoi/haoni.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+int m = 0;
+void move(int disk, char A, char C) {
+    m++;
+    printf("�� %d ���ƶ��� �� %d ��Բ�̴� %c �ƶ��� %c\n", m, disk, A, C);
+}
+void hanoi(int n, char A, char B, char C) {
+    if (n == 1) {
+        move(n, A, C);
+    }
+    else {
+        hanoi(n - 1, A, C, B);
+        move(n, A, C);
+        hanoi(n - 1, B, A, C);
+    }
+}
+
+int main() {
+    char A = 'A';
+    char B = 'B';
+    char C = 'C';
+    int disks;
+    printf("������Բ�̵ĸ���\n");
+    scanf("%d", &disks);
+    hanoi(disks, A, B, C);
+    return 0;
+}
+