第三章1、编一程序，按下式计算y的值，x的值由键盘输入。#include<stdio.h>#include<math.h>main(){floatx,y;printf("Pleaseinputx:");scanf("%f",&x);if(x>=0&&x<20)y=5*x+11;elseif(x>=20&&x<40)y=sin(x)+cos(x);elseif(x>=40&&x<60)y=exp(x);elseif(x>=60&&x<80)y=log(x+1);elsey=pow(x,4);printf("y=%f",y);}2、按工资的高低纳税，已知不同工资s的税率p如下：s<1000p=0%1000≤s<2000p=5%2000≤s<3000p=8%3000≤s<5000p=10%5000≤sp=15%编一程序，输入工资数，求纳税款和实得工资数。#include<stdio.h>main(){floatsalary,p,way;printf("Pleaseinputsalary:");scanf("%f",&salary);if(salary<1000)p=0;elseif(salary<2000)p=0.05;elseif(salary<3000)p=0.08;elseif(salary<5000)p=0.1;elsep=0.15;way=salary*(1-p);printf("p=%f,way=%f",p,way);}#include<stdio.h>main(){floatsalary,p,way;intt;printf("Pleaseinputsalary:");scanf("%f",&salary);t=salary/1000;switch(t){case0:p=0;break;case1:p=0.05;break;case2:p=0.08;break;case3:case4:p=0.1;break;default:p=0.15;break;}way=salary*(1-p);printf("p=%f,way=%f",p,way);}4、编写一个“猜猜看”程序。即给定一个样板数，比如123，让用户在键盘上输入整数，将其与样板数比较。如果相等，则输出“正确”字样；否则输出太大或太小的信息。main(){intnum,guess;printf("Pleaseinputmodel-number:");scanf("%d",&num);clrscr();printf("mode-number:***");printf("\nNowstart:");scanf("%d",&guess);while(guess!=num){if(guess>num)printf("\nTheguessishigh!");if(guess<num)printf("\nTheguessislow!");printf("\nContinue:");scanf("%d",&guess);}printf("Theguessisright!");}1、编程求,直到最后一项的绝对值小于10-6为止。2、编写程序，求任意输入的三个正整数的最小公倍数并输出。#include"stdio.h"main(){intnum1,num2,num3,sub,min_multiple,r;printf("\nPleaseinputthreenumber(num1,num2,num3):");scanf("%d,%d,%d",&num1,&num2,&num3);sub=num1*num2;r=num1%num2;while(r!=0){num1=num2;num2=r;r=num1%num2;}min_multiple=sub/num2;sub=min_multiple*num3;r=min_multiple%num3;while(r!=0){min_multiple=num3;num3=r;r=min_multiple%num3;}min_multiple=sub/num3;printf("min_multiple=%d",min_multiple);}3、相邻两个奇数都为素数的这样一对数叫双胞胎素数，输出100到200之间的所有双胞胎素数。4、编写程序实现用一元人民币换成一分、两分、五分的硬币共50枚。根据：根据：7、一个数如果恰好等于它的因子之和,这个数就称为“完数”.编程序找出1000之内的所有完数,并按下面的格式输出其因子:6itsfactorsare1,2,35.