王益龙

level1/p01_runningLetter/runningLetter.c

@@ -0,0 +1,66 @@
+#include <stdio.h>
+#include <windows.h>
+#include <time.h>
+#include <string.h>
+//constants
+enum{ N = 1000 , sleep_time = 50};
+char space[N];
+int i;
+//func
+int GetWidth();
+int abs(int x);
+//entertainment
+void DrawLine(int width);
+void ChangeColor(int cnt);
+
+int main(int argc, char const *argv[])
+{
+    printf("Please enter several letters within a line:\n");
+    //Init
+    char str[N]; scanf("%s",str);
+    int len = strlen(str);
+    int width = GetWidth();
+    int pos;
+    //Play
+    int cnt = 0;
+    while (1) {
+        /*calculate pos*/
+        pos = width - abs(width - ( cnt++ % (2 * width) ) );
+        /*prevent crossing the border*/
+        if (pos + len > width) continue;
+
+                    ChangeColor(cnt);
+        system("cls");
+                    DrawLine(width);
+        /*Output*/
+        for (i = 0; i < width; ++ i) 
+            space[i] = i < pos || i >= pos + len ? ' ' : str[i - pos];
+        space[i] = '\0';
+        printf("%s",space);
+
+                    DrawLine(width);
+        /*Sleep a while, let the user watch.*/
+        Sleep(sleep_time);
+    }
+    return 0;
+}
+int GetWidth()
+{
+    CONSOLE_SCREEN_BUFFER_INFO scr;
+    HANDLE hOut = GetStdHandle(STD_OUTPUT_HANDLE);
+    GetConsoleScreenBufferInfo(hOut, &scr);
+    return scr.dwMaximumWindowSize.X;
+}
+int abs(int x)
+{
+    return x >= 0 ? x : -x;
+}
+void DrawLine(int width)
+{
+    for (i = 0; i < width; ++ i) space[i] = '*'; space[i] = '\0';
+    printf("%s\n",space);
+}
+void ChangeColor(int cnt) {
+    SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE),cnt % 16);
+    // SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE),(cnt % 16) * 16 + 16 - (cnt % 16));
+}

level1/p02_isPrime/isPrime.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+int main(){
+    int n,i;
+    scanf("%d",&n);
+    if (n <= 1) {
+        printf("error");
+        return 0;
+    }
+    for (i = 2; i <= n / i; ++ i) {
+        if (n % i == 0) {
+            printf("Not prime.");
+            return 0;
+        }
+    }
+    printf("Is prime.");
+    return 0;
+}

level1/p03_Diophantus/Diophantus.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+int main(){
+    double t;
+    for (t = 5; ; ++ t) {
+        if (t / 6 + t / 12 + t / 7 + 5 + t / 2 + 4 == t) {
+            printf("%g\n",t - 4);
+            break;
+        }
+    }
+    system("pause");
+    return 0;
+}

level1/p04_ narcissus/narcissus.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+int is_narcissus(int x){
+    int a = x / 100;
+    int c = x % 10;
+    int b = (x - a * 100 - c) / 10;
+    if (x == a * a * a + b * b * b + c * c * c)
+    return 1;
+    else return 0;
+}
+int main(){
+    int i;
+    for (i = 100; i <= 999; ++ i) {
+        if (is_narcissus(i)) printf("%d\n",i);
+    }
+    system("pause");
+    return 0;
+}

level1/p05_allPrimes/allPrimes.c

@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include <time.h>
+enum {N = 1001};
+int primes[N], cnt;
+int sieved[N];    	
+
+void get_primes(int n);
+int main(int argc, char const *argv[])
+{
+    clock_t timer = clock();
+    get_primes(1000);
+    int i;
+    for (i = 0; i < cnt; ++ i) {
+        printf("%d\t",primes[i]);
+    }
+    printf("\nTime:%dms\n",clock() - timer);
+    system("pause");
+    return 0;
+}
+void get_primes(int n)
+{
+    int i,j;
+    for (i = 2; i <= n; i ++ )
+    {
+        if (!sieved[i]) primes[cnt ++ ] = i;
+        for (j = 0; primes[j] <= n / i; j ++ )
+        {
+            sieved[primes[j] * i] = 1;
+            if (i % primes[j] == 0) break;	
+        }
+    }
+}

level1/p06_Goldbach/Goldback.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+enum {N = 100};
+int sieved[N + 1];
+int primes[N + 1],cnt;
+int i,j,k,l;
+void init_primes();
+int main(){
+    init_primes();
+    for (i = 6; i <= N; ++ i){
+        for (j = 0; j < cnt; ++ j)
+            for (k = 0; k < cnt; ++ k)
+                for (l = 0; l < cnt; ++ l)
+                    if (primes[j] + primes[k] + primes[l] == i) {
+                        printf("%d == %d + %d + %d\n",i,primes[j],primes[k],primes[l]);
+                        goto flag;
+                    }
+        printf("It is wrong within 100!");
+        flag:
+        ;
+    }
+    printf("It is verified that Goldbach conjecture is right within 100.\n");
+    system("pause");
+    return 0;
+}
+void init_primes(){
+    for (i = 2; i <= N; ++ i) {
+        if (!sieved[i]) {
+            primes[cnt ++] = i;
+            for (j = i + i; j <= N; j += i)
+                sieved[j] = 1;
+        }
+    }
+}

level1/p07_encrypt_decrypt/encrypt_decrypt.c

@@ -0,0 +1,74 @@
+#include <stdio.h>
+#include <stdlib.h>
+char book[] = "18381048095";
+typedef struct string {
+    char * str;
+    int length;
+    int capacity;
+} string;
+void get_str(string * str);
+void init_str(string * str);
+void update(string * str);
+void encrypt(string * str);
+void decrypt(string * str);
+void showStr(string * str);
+int main(int argc, char const *argv[])
+{
+    printf("Please enter the letters:\n");
+    string * str = (string *)malloc(sizeof(string));
+    get_str(str);
+    char ch;
+    printf("Enter 'e' to encrypt it, 'd' to decrypt it and 'q' to quit.\n");
+    while (ch = getchar()) {
+        if (ch == 'q') break;
+        else if (ch == 'e') encrypt(str);
+        else if (ch == 'd') decrypt(str);
+        else if (ch == '\n') continue;
+        else {
+            printf("Invalid input!\n");
+            continue;
+        }
+        showStr(str);
+    }
+    return 0;
+}
+void showStr(string * str) {
+    int i;
+    for (i = 0; i < str->length; ++ i){
+        putchar(str->str[i]);
+    }
+    putchar('\n');
+}
+void encrypt(string * str) {
+    int i;
+    for (i = 0; i < str -> length; ++ i) str -> str[i] += book[i % 11] - '0';
+}
+void decrypt(string * str) {
+    int i;
+    for (i = 0; i < str -> length; ++ i) str -> str[i] -= book[i % 11] - '0';
+}
+void get_str(string * str) {
+    init_str(str);
+    char ch;
+    while (ch = getchar()) {
+        if (ch == '\n') break;
+        update(str);
+        str->str[str->length++] = ch;
+    }
+}
+void init_str(string * str) {
+    str -> length = 0;
+    str -> capacity = 10;
+    str -> str = (char*)malloc(sizeof(char) * str -> capacity);
+}
+void update(string * str) {
+    if (str -> length > str -> capacity - 3) {
+        str -> capacity += str -> capacity / 2;
+
+        char * p = (char*)malloc(sizeof(char) * str -> capacity);
+        int i;
+        for (i = 0; i < str -> length; ++ i)
+            p[i] = str -> str[i];
+        str -> str = p;
+    }
+}

level1/p08_hanoi/hanoi.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+void hanoi(int n,char origin,char medium,char dest) {
+    if (n == 1) {
+        printf("%c -> %c\n", origin, dest);
+        return;
+    }
+    hanoi(n-1,origin,dest,medium);
+    printf("%c -> %c\n", origin, dest);
+    hanoi(n-1,medium,origin,dest);
+}
+int main() {
+    int n = 3;
+    hanoi(n,'A','B','C');
+    return 0;
+}