《C语言程序设计》习题参考答案第4章习题参考答案判断题12345××√×√选择题123456BDBBDA程序阅读题105a=8abc123DEF程序填空题s=0t*10chch==')'count--count==0count>0div=ndiv—编程题#include<stdio.h>#include<math.h>main(){floata,b,c,x,s;printf("Inputa,bandc:");scanf("%f%f%f",&a,&b,&c);if(a+b<=c||a+c<=b||b+c<=a)printf("Error!\n");else{x=(a+b+c)/2;s=sqrt(x*(x-a)*(x-b)*(x-c));printf("area=%f\n",s);}}(2)#include<stdio.h>voidmain(){floatsalary,tax;intntax;printf("\nPleaseenterasalary=");scanf("%f",&salary);ntax=salary/500;if(ntax>=10)ntax=10;switch(ntax){case0:case1:tax=0;break;case2:tax=(salary-1000)*0.05;break;case3:case4:tax=500*0.05+(salary-1500)*0.1;break;case5:case6:tax=500*0.05+1000*0.1+(salary-2500)*0.15;break;case7:case8:case9:tax=500*0.05+1000*0.1+1000*0.15+(salary-3500)*0.20;break;case10:tax=500*0.05+1000*0.1+1000*0.15+1500*0.20+(salary-5000)*0.30;}printf("\nThetax=%10.2f\n",tax);}（3）方法一#include<stdio.h>#include<math.h>main(){inti=1;floatt=-1,s=0;do{t=-t/i;s=s+t;i=i+1;}while(fabs(t)>1e-6);printf("s=%f\n",s);}方法二#include<stdio.h>voidmain(){inti=1,sign=1;floatt=1.0,s=0.0;while(1.0/t>1e-6){t=t*i;s=s+sign/t;i=i+1;sign=-sign;};printf("s=%f\n",s);}（4）方法一:#include<stdio.h>main(){inti,a,b,c;for(i=100;i<=999;i++){a=i/100;b=i/10%10;c=i%10;if(i==a*a*a+b*b*b+c*c*c)printf("%d\n",i);}}方法二:#include<stdio.h>voidmain(){inti,a,b,c;for(a=1;a<=9;a++)for(b=0;b<=9;b++)for(c=0;c<=9;c++){i=a*100+b*10+c;if(i==a*a*a+b*b*b+c*c*c)printf("%d\n",i);}}（5）voidmain(){inti,k,j;for(i=1;i<=9;i++)/*外循环控制打印行数*/{for(k=1;k<=10-i;k++)/*每行起始打印位置*/printf("");for(j=1;j<=2*i-1;j++)/*内循环控制打印个数*/printf("%c",48+i);/*打印内容数字1的Ascii码为49*/printf("\n");/*换行*/}}（6）#include<stdio.h>main(){inta,b,c;for(a=0;a<=20;a++)for(b=0;b<=33;b++){c=100-a-b;if(a*5+b*3+c/3.0==100)printf("%d,%d,%d\n",a,b,c);}}（7）#include<stdio.h>#include<math.h>main(){floatx,x0,a;scanf("%f",&a);x=a;do{x0=x;x=2/3.0*x0+a/(3*