.;.初学C语言常用简单程序代码素数的筛选#include#include#defineN1000intmain(intargc,char*argv[]){inti,j,num[N];for(i=0;i.;.main(){intx,s,t,d;scanf("%d",&x);s=x%60;t=(x/60)%60;d=(x/60)/60;printf("%d时%d分%d秒",d,t,s);}三个数的交换#includevoidmain(){inta,b,c,t;scanf("%d%d%d",&a,&b,&c);printf("Theoriginalnumber:a=%d,b=%d,c=%d\n",a,b,c);t=a,a=b,b=t;t=a,a=c,c=t;printf("afterswap:a=%d,b=%d,c=%d",a,b,c);}switch语句的运用#includemain(){inta,m;printf("pleaseinputanumber:");scanf("%d",&a);switch(a/10){case10:case9:m=5;break;.;.case8:m=4;break;case7:m=3;break;case6:m=2;break;default:m=1;}printf("m=%d",m);}判断奇数和偶数#includemain(){intx;printf("Pleaseinputanumber:");scanf("%d",&x);if(x%2==0)printf("thisisaoushu!");elseprintf("thisisajishu!");}小写改大写，若是大写则不变includemain(){charc1,c2;printf("Inputaletter\n");scanf("%c",&c1);c2=('a'<=c1&&c1<='z')?(c1-'a'+'A'):c1;printf("%c",c2);getchar();return0;.;.}输入一个数，输出这个数是几位数#includemain(){intx,n;printf("pleaseinputanumber:");scanf("%d",&x);n=0;while(x!=0){x=x/10;n++;}printf("%d",n);}输入一个数，判断它是几位数，然后逆序输出#includeintmain(){intnum;intlen=0;inttemp=0;printf("Pleaseinputanumber:\n");scanf("%d",&num);while((num%10)!=0){temp=temp*10+(num%10);len++;.;.num=num/10;}printf("length=%d\n",len);printf("Reverseis%d",temp);}打印水仙花数#includemain(){intx,a,b,c;for(x=100;x<=999;x++){a=x%10;b=(x/10)%10;c=x/100;if(x==a*a*a+b*b*b+c*c*c){printf("%5d",x);}}printf("\n");}判断闰年#include"stdio.h"main(){intk,flag,n=0;for(k=1980;k<=2880;k++).;.{flag=(k%4==0)&&(k%100!=0)||(k%400==0);if(flag){printf("%5d",k);n++;if(n%10==0)printf("\n");}}printf("\n");}求1-3+5-7...-99+101的值#includemain(){intsum,i,t;sum=1;t=1;for(i=3;i<=101;i=i+2){t=-t;sum=sum+t*i;}printf("sum=%d",sum);}求前n项和#includemain(){floats,t;.;.intn,i,fz,fm;s=0;fz=2;fm=1;printf("Entern:");scanf("%d",&n);for(i=1;i<=n;i++){t=(1.0*fz)/fm;s=s+t;fz=fz+fm;fm=fz-fm;}printf("s=%f\n",s);}开发一个程序求全班学生某门课的平均成绩，要求程序每次运行时班级人数可为任意/*用标记值来指示数据输入的结束*/#includemain(){floataverage,total;intcounter,score;total=0.0;counter=0;printf("输入成绩,-1表示结束:");scanf("%d",&score);while(score!=-1)/*用-1表示输入的结束,同时循环输入分数*/{.;.total=total+score;counter++;printf("输入下一个成绩,-1表示输入结束:");scanf("%d",&score);}if(counter!=0){average=total/counter;printf("全班平均成绩为：%.2f\n",average);}elseprintf("没有输入成绩\n");return0;}求二元一次方程的根#include#includemain(){floata=4,b=-40,c=91;floatx1,x2;floatdelta;delta=sqrt(b*b-4.0*a*c);x1=(-b+delta)/(2.0*a);x2=(-b-delta)/(2.0*a);printf("x1=%fx2=%f\n",x1,x2);.;.}if语句的运用#includemain(){inta,b,c,s,w,t;s=w=t=0;a=-1;b=c=3;if(c>0)s=a+b;if(a<=0){if(b>0)if(c<=0)w=a-b;}elseif(c>0)w=a-b;elset=c;printf("s=%d,w=%d,t=%d",s,w,t);}输入学生的生日，输出他的实足年龄#includemain(){inty0,m0,d0,y1,m1,d1,age;.;.printf("\npleaseinputbirthday(yyyy/mm/dd):");scanf("%d/%d/%d",&y0,&m0,&d0);printf("\npleaseinputcurrentday(yyyy/mm/dd):");scanf("%d/%d/%d",&y1,&m1,&d1...
