实验3
ex1:
1 # include<math.h> 2 # include<stdio.h> 3 4 int main(){ 5 float a,b,c,x1,x2; 6 float delta,real,imag; 7 8 printf("Enter a,b,c:"); 9 10 while(scanf("%f%f%f",&a,&b,&c)!=EOF){ 11 if (a==0) 12 printf("not quadratic equation.\n\n"); 13 else{ 14 delta=b*b-4*a*c; 15 16 if(delta>=0){ 17 x1 = (-b + sqrt(delta)) / (2*a); 18 x2 = (-b - sqrt(delta)) / (2*a); 19 printf("x1=%.2f,x2=%.2f\n\n",x1,x2); 20 } 21 else{ 22 real=-b/(2*a); 23 imag=sqrt(-delta)/(2*a); 24 printf("x1=%.2f+%.2fi,x2=%.2f-%.2fi\n\n",real,imag,real,imag); 25 } 26 } 27 printf("Enter a,b,c:"); 28 } 29 return 0 ; 30 }
ex2:
1 #include<stdio.h> 2 #include<stdlib.h> 3 #include<time.h> 4 #define N 5 5 6 int main(){ 7 int x,n; 8 9 srand(time(0)); 10 n=0; 11 do{ 12 n++; 13 x=rand()%10; 14 printf("%3d",x); 15 }while(n<N); 16 printf("\n"); 17 18 return 0; 19 }
ex3:
1 #include<stdio.h> 2 #include<math.h> 3 int main() 4 { 5 int m,n,h=0; 6 for(n=101;n<=200;n++) 7 { 8 for(m=2;m<=sqrt(n);++m) 9 if(n%m==0)break; 10 if(m>sqrt(n)) 11 { 12 printf("%5d",n); 13 h++; 14 if(h%5==0) 15 printf("\n"); 16 } 17 18 } 19 20 printf("\n101~200有%d个素数",h); 21 return 0; 22 }
ex4:
1 #include<stdio.h> 2 #include<math.h> 3 int main(){ 4 long m,n,b; 5 printf("Enter a number:"); 6 while(scanf("%d",&n)!=EOF) 7 { 8 int k=0,b=0; 9 do 10 { 11 m=n%10; 12 if(n%2!=0) 13 { 14 b=b+m*pow(10,k); 15 k++; 16 } 17 n=n/10; 18 }while(n!=0); 19 printf("new number is:%d",b); 20 printf("\n\nEnter a number:"); 21 } 22 return 0; 23 }
求余数得出各位上的数并除以2判断奇偶,最后用递增的幂数来排列高低位次。
ex5:
1 #include<stdio.h> 2 #include<math.h> 3 int getfactorial(int n); 4 int main() 5 { 6 int m,n; 7 float a=0,b=1; 8 printf("Enter n(1~10):"); 9 while(scanf("%d",&n)!=EOF) 10 { 11 for(m=1;m<=n;m++) 12 { 13 b=b*m; 14 a=a+pow(-1,m-1)*(1/b); 15 } 16 printf("n=%d,s=%f\n",n,a); 17 printf("\nEnter n(1~10):"); 18 } 19 return 0; 20 } 21
ex6:
1 #include<stdlib.h> 2 #include<stdio.h> 3 #include<time.h> 4 int main() 5 { 6 int m,n,k; 7 srand(time(0)); 8 k=1+rand()%30; 9 n=0; 10 printf("猜猜2020年12月哪一天会是你的luck day\n"); 11 printf("\n开始喽,你有三次机会,猜吧(1~31):"); 12 scanf("%d",&m); 13 while(n<=3) 14 { 15 if(m>k) 16 { 17 18 printf("\n你猜的日期晚了,luck day悄悄溜到前面啦\n"); 19 printf("\n再猜(1~31):"); 20 scanf("%d",&m); 21 n++; 22 } 23 else if(m<k) 24 { 25 26 printf("\n你猜的日期早了,luck day还没到呢\n"); 27 printf("\n再猜(1~31);"); 28 scanf("%d",&m); 29 n++; 30 } 31 else 32 printf("\n猜中了,nice!"); 33 n++; 34 } 35 printf("\n次数用完啦。偷偷告诉你:12月,你的luck day是%d号",k); 36 return 0; 37 }