11.16 实验三(任务1，2）

#include<math.h>
#include<stdio.h>
int main(){    
    float a,b,c,x1,x2;
    float delta,real,imag;
    printf("Enter a,b,c:");
    while(scanf("%f%f%f",&a,&b,&c)!=EOF) {
        if(a==0)
        printf("不是二元方程.\n\n");
        else{
            delta=b*b-4*a*c;
            if(delta>=0){
                x1=(-b+sqrt(delta))/(2*a);
                x1=(-b-sqrt(delta))/(2*a);
            printf("x1=%.2f,x2=%.2f\n\n",x1,x2);
            }
            else{
                real=-b/(2*a);
                imag=sqrt(-delta)/(2*a);
                printf("x1=%.2f+%.2fi,x2=%.2f-%.2fi\n\n",real,imag,real,imag);
            }
        }
    printf("Enter,a,b,c");
    }
    return 0;
}
     

#include<stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 5
     int main() {
        int x, n;
        srand(time(0));  
        n = 0;
          do {
          n++;
          x = rand()%10;  
          printf("%3d", x);
}
        while(n<N);
        printf("\n");
        return 0;
}