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1 #include <math.h>
2 #include <stdio.h>
3
4 int main()
5 {
6 float a, b, c, x1, x2;
7 float delta, real, imag;
8
9 printf("Enter a, b, c: ");
10
11 while(scanf("%f%f%f", &a, &b, &c) != EOF)
12 {
13 if(a == 0)
14 { printf("not quadratic equation.\n\n"); }
15 else
16 { delta = b*b - 4*a*c; }
17
18 if(delta >= 0)
19 {
20 x1 = (-b + sqrt(delta)) / (2*a);
21 x2 = (-b - sqrt(delta)) / (2*a);
22 printf("x1 = %.2f, x2 = %.2f\n\n", x1, x2);
23 }
24 else
25 {
26 real = -b/(2*a);
27 imag = sqrt(-delta) / (2*a);
28 printf("x1 = %.2f + %.2fi, x2 = %.2f - %.2fi\n\n", real,imag,real,imag);
29 }
30
31 printf("Enter a, b, c: ");
32 }
33
34 return 0;
35 }
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1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <time.h>
4 #define N 5
5 int main() {
6 int x, n;
7
8 srand(time(0)); // 以当前系统时间作为随机种子
9 n = 0;
10
11 do {
12 n++;
13 x = rand()%10; // 生成一个0~9之间的随机整数
14 printf("%3d", x);
15 }while(n<N);
16
17 printf("\n");
18
19 return 0;
20 }
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1 #include <stdio.h>
2 #include <math.h>
3
4 int main()
5 {
6 int n=100,a=0,m=2;
7
8 while(n<200)
9 {
10 while(m <=sqrt(n))
11 {
12 if(n%m!=0)
13 {m+=1;}
14 else
15 {break;}
16 }
17 if(m>sqrt(n))
18 {
19 printf("%d\n",n);
20 a+=1;
21 }
22 n+=1;
23 m=2;
24 }
25 printf("个数为%d",a);
26
27 return 0;
28 }
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1 #include <stdio.h>
2 #include <math.h>
3
4 int main()
5 {
6 int a,b,c,sum=0,n=0;
7
8 while(scanf("%d",&a) != EOF)
9 {
10
11 while(a>0)
12 {
13 b=a%10;
14 a/=10;
15 if(b==1||b%2==1)
16 {
17 c=b*pow(10,n);
18 n+=1;
19 sum+=c;
20 }
21 }
22 printf("%d\n",sum);
23 printf("\n");
24 sum=0;
25 n=0;
26 }
27
28 return 0;
29 }
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1 #include <stdio.h>
2 #include <math.h>
3
4 int f(int);
5 int f(int k)
6 {
7 int m=k;
8
9 if (k > 1)
10 {
11 while (k > 1)
12 {
13 m = m* (k - 1);
14 k = k - 1;
15 }
16 }
17 else
18 m = 1;
19
20
21 return m;
22 }
23
24
25 int main()
26 {
27 int n,x;
28 double a = 1,sum=0;
29
30 while (scanf("%d", &n)!=EOF)
31 {
32 if (n < 1 || n>10)
33 {
34 printf("请输入1到10间的数字");
35 }
36 else
37 {
38 while (n > 0)
39 {
40 x = f(n);
41 sum += a / x * pow(-1, n - 1);
42 n = n - 1;
43 }
44 }
45
46 printf("%lf\n", sum);
47 printf("\n") ;
48 a = 1;
49 sum = 0;
50 }
51
52
53 return 0;
54 }
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1 #include <stdio.h>
2 #include <stdlib.h>
3
4 int main()
5 {
6 int a,b,k=1;
7 a=rand()%32;
8
9 while(k<4)
10 {
11 scanf("%d",&b);
12 k+=1;
13
14 if(b==a)
15 {
16 printf("猜对了\n");
17 break;
18 }
19 else if(b<a)
20 {printf("猜小了\n");}
21 else
22 {printf("猜大了\n");}
23 }
24
25 if(k==4)
26 {printf("次数用完,答案为%d",a);}
27 else
28 {printf("猜对了,答案为%d",a);}
29
30 return 0;
31 }