C語言經(jīng)典例題及答案

PAGE作業(yè)一求一個任意邊長的矩形面積。#include<stdio.h>voidmain(){intw,h,sum;scanf("%d%d",&w,&h);sum=w*h;printf("area=%d\n",sum);}求一個任意半徑的圓的面積及周長。#definePI3.14159#include<stdio.h>voidmain(){floatr,area,c;scanf("%f",&r);area=PI*r*r;c=2*PI*r;printf("area=%f\ncircle=%f\n",area,c);}已知：w=5,y=4,z=2,求表達式：w*y/z的值，并輸出。##include<stdio.h>voidmain(){intw,y,z,r;w=5;y=4;z=2;r=w*y/z;printf("%5d",r);}作業(yè)二從鍵盤上輸入三個數(shù)，求出其中的最大值，并輸出。#include<stdio.h>voidmain(){inta,b,c,max;scanf("%d%d%d",&a,&b,&c);max=a;if(max<b)max=b;if(max<c)max=c;printf("max=%d\n",max);}求sin300。+sin600+cos300+cos600之和。（注意：30*3.14159/180）#include<stdio.h>#definePI3.14159#include<math.h>voidmain(){floata,b,sum;a=30*PI/180;b=60*PI/180;sum=sin(a)+sin(b)+cos(a)+cos(60);printf("total=%f\n",sum);}比較兩個數(shù)的大小。如果x大于y，則輸出：x>y，否則輸出：x<y。#include<stdio.h>voidmain(){intx,y;scanf("%d,%d",&x,&y);if(x>y)printf("x>y\n");elseprintf("x<y\n");}作業(yè)三輸入a、b、c三個值，按從小到大排序輸出。#include<stdio.h>voidmain(){inta,b,c,t;scanf("%d%d%d",&a,&b,&c);if(a>b){t=b;b=a;a=t;}if(a>c){t=a;a=c;c=t;}if(b>c){t=b;b=c;c=t;}printf("%3d%3d%3d\n",a,b,c);}.求自然數(shù)1～10之和。。#include<stdio.h>voidmain(){inti,sum;i=1;sum=0;while(i<=10){ sum=sum+i; i++;}printf("sum=%d\n",sum);}輸入10個整數(shù)，統(tǒng)計出正數(shù)之和以及負數(shù)之和。（求奇數(shù)之和以及偶數(shù)之和）#include<stdio.h>voidmain(){intsum1=0,sum2=0,i,x;i=1;while(i<=10){scanf("%d",&x);if(x%2==0)sum1=sum1+x;elsesum2=sum2+x;i++;}printf("sum1=%d\nsum2=%d\n",sum1,sum2);}作業(yè)四輸入一個0～6的整數(shù)，轉(zhuǎn)換成星期輸出。#include<stdio.h>main(){inta;scanf("%d",&a);switch(a){case0:printf("Sunday");break;case1:printf("Monday");break;case2:printf("Tuesday");break;case3:printf("Wednesday");break;case4:printf("Thursday");break;case5:printf("Friday");break;case6:printf("saturday");break;default:printf("Iamsorry.Youarewrong.\n");}}.輸入一個整數(shù)，將各位數(shù)字反轉(zhuǎn)后輸出。如：輸入365，則輸出顯示為563。#include<stdio.h>voidmain(){intx,r;scanf("%d",&x);printf("converis:");while(x!=0){r=x%10;printf("%d",r);x=x/10;}printf("\n");}輸入一個整數(shù)，求出它的所有因子。#include<stdio.h>voidmain(){ intx,i; scanf("%d",&x); for(i=1;i<=x;i++) if(x%i==0) printf("%3d",i);}作業(yè)五求100～200之間的素數(shù)。#include<stdio.h>#include<math.h>voidmain(){intj=0,x,n,i;for(x=100;x<=200;x++){n=sqrt(x);for(i=2;i<=n;i++){if(x%i==0)break;}if(i>n){printf("%5d",x);j++;}if(j%5==0)printf("\n");}}編程輸出三角形的9×9乘法表。#include<stdio.h>voidmain(){ inti,j; for(i=1;i<10;i++) { for(j=1;j<=i;j++) printf("%d*%d=%d",i,j,i*j); printf("\n"); }}求任意二個數(shù)的最大公約數(shù)。#include<stdio.h>main(){inta,b,m,n,q;scanf("%d%d",&m,&n);a=m;b=n;if(a>b){intz;z=a;a=b;b=z;}do{q=b%a;b=a;a=q;}while(q!=0);printf("%d\n",b);}作業(yè)六利用循環(huán)語句求（直到第100項的和）。#include<stdio.h>voidmain(){inti,t=1;floats=1,p=0,n=1;for(i=1;i<=100;i++){p=p+s;n=n+2;t=-t;s=t/n;}printf("%f\n",p);}編寫求S=。#include<stdio.h>voidmain(){intx,y=0,n,i;for(n=1;n<=5;n++){x=1;for(i=1;i<=n;i++)x=x*i;y=y+x;}printf("%d\n",y);}利用公式求cosx的近似值（精度為10-6）：#include<stdio.h>#include<math.h>voidmain(){floatn=1,t=1,pi=0,s=1,x,i=1;scanf("%f",&x);while(fabs(t)>=1e-6){pi+=t;n=n*i*(i+1);s=-s*x*x;i++;t=s/n;}printf("%f",pi);}作業(yè)七用選擇法對10個整數(shù)排序（由大到小）。#include<stdio.h>voidmain(void){inta[10],i,j,t;for(i=0;i<10;i++)scanf("%d",&a[i]);for(i=0;i<9;i++)for(j=0;j<9-i;j++)if(a[j]>a[j+1]){t=a[j];a[j]=a[j+1];a[j+1]=t;}for(i=0;i<10;i++)printf("%6d",a[i]);printf("\n");}輸入10個學生的一門課成績，用一維數(shù)組存放其成績，統(tǒng)計并輸出不及格人數(shù)及其百分比。#include<stdio.h>voidmain(void){inti,count=0;floatscore[10],percent;for(i=0;i<10;i++)scanf("%d",&a[i]);for(i=0;i<10;i++) if(score[i]<60) count++;percent=(float)count/10;printf("%d,%5.1f",count,percent);}編程實現(xiàn)N階方陣轉(zhuǎn)置。#include<stdio.h>voidmain(){inta[3][3],b[3][3],i,j;for(i=0;i<3;i++)for(j=0;j<3;j++)scanf("%d",&a[i][j]);for(i=0;i<3;i++)for(j=0;j<3;j++)b[j][i]=a[i][j];printf("\n");for(i=0;i<3;i++){for(j=0;j<3;j++)printf("%4d",b[i][j]);printf("\n");}}作業(yè)八把輸入的一個字符串按逆序重新排序其字符，并輸出。#include<stdio.h>#include<string.h>voidmain(){chara[80],k;inti,j;gets(a);for(i=0,j=strlen(a)-1;i<j;i++,j--){k=a[i];a[i]=a[j];a[j]=k;}puts(a);}從鍵盤輸入一個字符串。要求分別統(tǒng)計出其中英文大寫字母、小寫字母、數(shù)字、空格、以及其它字符的個數(shù)#include<stdio.h>voidmain(){inti,a=0,b=0,c=0,d=0,e=0;charq[20];gets(q);for(i=0;q[i]!='\0';i++){if(q[i]>='0'&&q[i]<='9') a++;elseif(q[i]>='a'&&q[i]<='z') b++;elseif(q[i]>='A'&&q[i]<='Z') c++;elseif(q[i]=='') d++;elsee++;}printf("%3d%4d%3d%3d%3d",a,b,c,d,e);}輸入五個英文單詞，請找出它們之中按字典排序法排在最前的一個詞。#include<stdio.h>#include<string.h>voidmain(){chara[5][30],b[30];inti,j,k;for(i=0;i<5;i++)gets(a[i]);for(i=0;i<5;i++){k=i;strcpy(b,a[i]);for(j=i+1;j<5;j++)if(strcmp(a[j],b)<0){k=j; strcpy(b,a[j]);}if(k!=i){strcpy(b,a[i]); strcpy(a[i],a[k]); strcpy(a[k],b);}puts(a[i]);}printf("\n");}作業(yè)九一、編寫一函數(shù)，將字符串中的小寫字母轉(zhuǎn)換為大寫字母，主函數(shù)輸入字符串并輸出結(jié)果。#include<stdio.h>charchange(chara[]){inti;for(i=0;a[i]!='\0';i++)if(a[i]>='a'&&a[i]<='z')a[i]=a[i]-32;}voidmain(){charb[80];gets(b);change(b);puts(b);}二、編寫一函數(shù)求N！。在主函數(shù)中輸入N，調(diào)用函數(shù)求N！，輸出結(jié)果。#include<stdio.h>intsum(intn){inti,pi=1;for(i=1;i<=n;i++)pi=pi*i;return(pi);}voidmain(){intp=0,n;scanf("%d",&n);p=sum(n);printf("%d\n",p);}三、編寫一個函數(shù)，求二維數(shù)組所有元素的和，要求二維數(shù)組的行、列以及數(shù)組通過函數(shù)參數(shù)傳遞，并通過主函數(shù)調(diào)用求2行3列的數(shù)組的所有元素之和。#include<stdio.h>intnum(inta[2][3],intn,intm){intsum=0,i,j;for(i=0;i<n;i++)for(j=0;j<m;j++)sum=sum+a[i][j];return(sum);}voidmain(){inta[2][3],i,j;intp=0,n=2,m=3;for(i=0;i<2;i++)for(j=0;j<3;j++)scanf("%d",&a[i][j]);p=num(a,n,m);printf("%d",p);}作業(yè)十一、編寫程序，通過函數(shù)求6–300以內(nèi)的素數(shù)的和。#include<stdio.h>#include<math.h>voidmain(){inti,sum=0;intper(int);for(i=6;i<=300;i++)sum=sum+per(i);printf("SUM=%d\n",sum);}intper(intn){intk,i;k=sqrt(n);for(i=2;i<=k;i++)if(n%i==0)break;if(i>=k+1)returnn;elsereturn0;}/*8265*/二、求sin300。+sin600+cos300+cos600之和。(自編sin和cos函數(shù))#include<stdio.h>#include<math.h>#definePI3.14159voidmain(){floaty,x30,x60;floatsin1(float);floatcos1(float);x30=30*PI/180;x60=60*PI/180;y=sin1(x30)+cos1(x30)+sin1(x60)+cos1(x60);printf("SUM=%f\n",y);}floatsin1(floatx){floatsum=0,t=x;inti=1,f=1;do{sum=sum+t;i=i+2;f=-f;t=t*f*x*x/(i*(i-1));}while(fabs(t)>1e-6);returnsum;}floatcos1(floatx){floatsum=0,t=1;inti=0,f=1;do{sum=sum+t;i=i+2;f=-f;t=t*f*x*x/(i*(i-1));}while(fabs(t)>1e-6);returnsum;}/*SUM=2.608201*/三、編寫函數(shù)，求級數(shù)S=1+2+3+...n，并在主函數(shù)中求：#include<stdio.h>intf(int);voidmain(){floats;s=(float)(f(3)+f(4)+f(5))/(f(5)+f(6)+f(7));printf("SUM=%f\n",s);}intf(inta){intsum=0,i;for(i=1;i<=a;i++)sum=sum+i;returnsum;}/*SUM=0.484375*/作業(yè)十一編寫一個函數(shù)，求一維數(shù)組的平均值、最大值。#include<stdio.h>voidmain(){inta[5],i,max;voidmaxave(intw[5],int*p,float*q);floatave=0;for(i=0;i<5;i++)scanf("%d",&a[i]);maxave(a,&max,&ave);printf("MAX=%d,AVER=%f\n",max,ave);}voidmaxave(intw[5],int*p,float*q){inti;*p=w[0];for(i=1;i<5;i++)if(*p<w[i])*p=w[i];for(i=0;i<5;i++)*q=*q+w[i];*q=*q/5;}輸入10個數(shù)，編寫一個函數(shù)，按降序?qū)ζ渑判?，統(tǒng)計其中大于平均值的數(shù)的個數(shù)。#include<stdio.h>intsort(intw[],intn);voidmain(){inti,a[10],count=0;for(i=0;i<10;i++)scanf("%d",&a[i]);count=sort(a,10);for(i=0;i<10;i++)printf("%3d",a[i]);printf("\nCOUNT=%d\n",count);}intsort(intw[],intn){inti,j,t,c=0;floatav=0;for(i=0;i<n-1;i++)for(j=i+1;j<n;j++)if(w[i]<w[j]){t=w[i]; w[i]=w[j]; w[j]=t; }for(i=0;i<n;i++)av=av+w[i];av/=10;for(i=0;i<n;i++)if(w[i]>av)c++;returnc;}編寫一個函數(shù)，求N階二維矩陣的主和輔對角線元素之和。#include<stdio.h>#defineN3voidmain(){inta[N][N],i,j,sum,sun;for(i=0;i<N;i++)for(j=0;j<N;j++) scanf("%d",&a[i][j]);for(i=0;i<N;i++){for(j=0;j<N;j++)printf("%3d",a[i][j]);printf("\n");}sum=zdj(a,N);sun=fdj(a,N);printf("sum=%d,sun=%d\n",sum,sun);}intzdj(intc[][N],intn){inti,s=0;for(i=0;i<n;i++)s+=c[i][i];returns;}intfdj(intd[][N],intn){inti,j,s=0;for(i=0;i<n;i++)for(j=0;j<n;j++)if(i+j==n-1)s+=d[i][j];returns;}作業(yè)十二用指針的方法，把輸入的一個字符串按逆序重新排序其字符，并輸出。#include<stdio.h>#include<string.h>voidmain(){charw[20],ch,*b,*e,*s;inti;s=b=w;gets(w);i=strlen(w);e=s+i-1;for(;b<e;b++,e--){ch=*b;*b=*e;*e=ch;}puts(s);}用指針的方法，將鍵盤輸入的兩個字符串連接起來形成一個新字符串。#include<stdio.h>#include<string.h>voidmain(){chara[30],b[20],*p,*q,*s;inti,j;p=s=a;q=b;gets(p);gets(q);i=strlen(p);p=p+i;while(*p++=*q++);puts(s);}用指針的方法，將鍵盤上輸入的一串數(shù)值字符串轉(zhuǎn)換為數(shù)值輸出。如輸入：‘-132’，則輸出為：-132。#include<stdio.h>#include<string.h>voidmain(){chara[10],*p;intt=1,n=0;gets(a);p=a;if(*p=='-'){t=-t;p++;}while(*p!='\0'){n=n*10+(*p-'0');p++;}n=n*t;printf("%d\n",n);} 作業(yè)十三通過函數(shù)統(tǒng)計某字符串中，英文單詞的個數(shù)。（參考p69）#include<stdio.h>#defineYES1#defineNO0voidmain(){intnl,nw,nc,inword;charc;inword=NO;nl=nw=nc=0;while((c=getchar())!='*'){++nc;if(c=='\n') ++nl;if(c==''||c=='\t'||c=='\n') inword=NO;else if(inword==NO) {inword=YES; ++nw; }}nl++;nc++;printf("%d\t%d\t%d\n",nl,nw,nc);} 在主函數(shù)中初始化一個3行4列的矩陣并將每個元素都輸出，然后調(diào)用子函數(shù)，分別計算每一行的元素之和，將和直接存放在每行的第一個元素中，返回主函數(shù)之后輸出各行元素的和。#include<stdio.h>voidmain(){inta[3][4],i,j;voidsum(intw[][4],intn,intm);for(i=0;i<3;i++)for(j=0;j<4;j++)scanf("%d",&a[i][j]);for(i=0;i<3;i++){for(j=0;j<4;j++)printf("%3d",a[i][j]);printf("\n");}sum(a,3,4);for(i=0;i<3;i++){printf("%3d",a[i][0]);printf("\n");}}voidsum(intw[][4],intn,intm){inti,j;for(i=0;i<n;i++)for(j=1;j<m;j++)w[i][0]+=w[i]