实验三

 1 #include<stdio.h>
 2 #include<math.h>
 3 int main() {
 4     float a, b, c, x1, x2;
 5     float delta, real, imag;
 6     printf("Enter a, b, c:  ");
 7         while (scanf_s("%f%f%f", &a, &b, &c) != EOF) {
 8             if (a == 0)printf("no quadratic equation.\n\n");
 9             else delta = b * b - 4 * a * c;
10 
11             if (delta >= 0) {
12 
13                 x1 = (-b + sqrt(delta)) / 2 * a;
14                 x2 = (-b - sqrt(delta)) / 2 * a;
15                 printf("x1=%.2f,x2=%.2f\n\n", x1, x2);
16             }
17             else {
18                 real = -b / (2 * a);
19                 imag = sqrt(-delta) /(2 * a);
20                 printf("x1=%.2f+%.2fi,x2+%.2f+%.2fi\n\n", real, imag, real, imag);
21             }
22 
23             printf("Enter a, b, c:  ");
24 
25         }
26 
27 
28     return 0;
29 }

 1 #include<stdio.h>
 2 #include<time.h>
 3 #include<stdlib.h>
 4 #define N 5
 5 int main() {
 6     int x, n=0;
 7     time_t timer = time(NULL);
 8     srand((size_t)timer);
 9     do {
10         n++;
11         x = rand() % 10;
12         printf("%3d", x);
13     } while (n < N);
14 
15     printf("\n");
16 
17     return 0;
18 }

 1 #include<stdio.h>
 2 #include<math.h>
 3 int main() {
 4     int n, i,t=0;
 5     for ( i = 1; i < 101; i++)
 6     {
 7         int m = i + 100,flag=1;
 8 
 9         for (int k = 2; k <= sqrt(m); k++)
10         {
11             if (m% k == 0) {
12                 flag = 0;
13                 break;
14             }
15         }
16 
17         if (flag) {
18             printf("%5d", m);
19             t++;
20             if (t % 5 == 0)printf("\n");
21         }
22         
23     }
24 
25     printf("\n  101~200之间共有%d,个素数.\n", t);
26 
27     return 0;
28 }

 1 #include<stdio.h>
 2 int main() {
 3     long s;
 4     int p;
 5     printf("Enter a number:");
 6 
 7     while (scanf_s("%ld", &s) != EOF) {
 8         long t = 1,new=0;
 9 
10         while (s != 0) {
11             p = s % 10;
12 
13             if (p % 2 != 0) {        //用%来判断奇偶
14                 new = new + p * t;   // 由于取出的p是低位的数，
15                 t = t * 10;                 //想顺序输出要借助t来表示位数，t*10就是位数向左进一
16             }
17 
18             s = s / 10;
19         }
20 
21         printf("new number is: %ld\n\n", new);
22         printf("Enter a number:");
23     }
24 
25     return 0;
26 }

 1 #include<stdio.h>
 2 int main() {
 3     
 4     double s;
 5     int n,sign,jc;
 6 
 7     printf("Enter n(1~10):");
 8 
 9     while (scanf_s("%d", &n) != EOF) {
10 
11         s = 0.0, sign = 1;
12 
13         for (int i = 1; i <= n; i++)
14         {
15             jc = 1;
16             for (int k = 1; k <= i; k++) jc *= k;
17 
18             s = s + sign / (double)jc;
19             sign = -sign;
20         }
21 
22         printf("n = %d,s=%lf\n\n", n, s);
23         printf("Enter n(1~10):");
24     }
25 
26     return 0;
27 }

 1 #include<stdio.h>
 2 #include<time.h>
 3 #include<stdlib.h>
 4 int main(){
 5 
 6     time_t timer = time(NULL);
 7     srand((size_t)timer);
 8 
 9     int n = rand() % 31 + 1;
10     int guess,flag=0;
11     printf("猜猜2020年12月哪一天会是你的lucky day\n\n");
12     printf("开始了，你有三次机会(1~31):");
13         for (int i = 0; i < 3; i++)
14         {
15             scanf_s("%d", &guess);
16             if (guess == n)
17             {
18                 printf("\n\n恭喜你猜中了!\n\n");
19                 flag = 1;
20                 break;
21             }
22             else if (guess > n)printf("\n你猜的日期晚了，lucky day 在前面。。。\n\n");
23             else printf("\n你猜的日期早了，lucky day还没到\n\n");
24             if(i<=1)printf(" 再猜(1~31):");
25         }
26         if (flag == 0)printf("次数用完了，悄悄告诉你：12月，你的lucky day是%d号", n);
27 
28 
29     return 0;
30 }

posted on 2020-11-12 21:44 wlj23 阅读(107) 评论(2) 收藏举报