C語(yǔ)言必背的經(jīng)典程序

C語(yǔ)言必背18個(gè)經(jīng)典程序1、/*輸出9*9口訣。共9行9列，i控制行，j控制列。*/#include<stdio.h>intmain(){ inti,j,result; for(i=1;i<10;i++) { for(j=1;j<10;j++) { result=i*j; printf("%d*%d=%-3d",i,j,result); } printf("\n");/*每一行后換行*/ }}2、/*古典問(wèn)題：有一對(duì)兔子，從出生后第3個(gè)月起每個(gè)月都生一對(duì)兔子，小兔子長(zhǎng)到第三個(gè)月后每個(gè)月又生一對(duì)兔子，假如兔子都不死，問(wèn)每個(gè)月兔子總數(shù)為多少？兔子規(guī)律為數(shù)列1,1,2,3,5,8,13,21....*/#include<stdio.h>intmain(){ longf1,f2; inti; f1=f2=1; for(i=1;i<=20;i++) { printf("%12ld%12ld",f1,f2); if(i%2==0)printf("\n");/*控制輸出，每行四個(gè)*/ f1=f1+f2;/*前兩個(gè)月加起來(lái)賦值給第三個(gè)月*/ f2=f1+f2;/*前兩個(gè)月加起來(lái)賦值給第三個(gè)月*/ }}3、/*判斷101-200之間有多少個(gè)素?cái)?shù)，并輸出全部素?cái)?shù)及素?cái)?shù)個(gè)數(shù)。程序分析：判斷素?cái)?shù)方法：用一個(gè)數(shù)分別去除2到sqrt(這個(gè)數(shù))，假如能被整除，則表明此數(shù)不是素?cái)?shù)，反之是素?cái)?shù)。*/#include<stdio.h>intmain(){ intm,i,k,h=0,leap=1; for(m=101;m<=200;m++) { k=sqrt(m+1); for(i=2;i<=k;i++) if(m%i==0) {leap=0;break;} if(leap){ printf("%-4d",m);h++; if(h%10==0) printf("\n"); } leap=1; } printf("\nThetotalis%d",h); return0;}4、/*一個(gè)數(shù)假如恰好等于它因子之和，這個(gè)數(shù)就稱為“完數(shù)”。比如6=1＋2＋3.編程找出1000以內(nèi)全部完數(shù)。*/#include<stdio.h>intmain(){ staticintk[10]; inti,j,n,s; for(j=2;j<1000;j++) { n=-1; s=j; for(i=1;i<j;i++) { if((j%i)==0) { n++; s=s-i; k[n]=i; } } if(s==0) { printf("%disawanshu:",j); for(i=0;i<n;i++) printf("%d,",k[i]); printf("%d\n",k[n]); } }}5、/*下面程序功效是將一個(gè)4×4數(shù)組進(jìn)行逆時(shí)針旋轉(zhuǎn)90度后輸出，要求原始數(shù)組數(shù)據(jù)隨機(jī)輸入，新數(shù)組以4行4列方式輸出，請(qǐng)?jiān)诳瞻滋幫晟瞥绦颉?/#include<stdio.h>intmain(){ inta[4][4],b[4][4],i,j; printf("input16numbers:"); for(i=0;i<4;i++) for(j=0;j<4;j++) { scanf("%d",&a[i][j]); b[3-j][i]=a[i][j]; } printf("arrayb:\n"); for(i=0;i<4;i++) { for(j=0;j<4;j++) printf("%6d",b[i][j]);printf("\n");}}6、/*編程打印直角楊輝三角形*/#include<stdio.h>intmain(){ inti,j,a[6][6]; for(i=0;i<=5;i++) {a[i][i]=1;a[i][0]=1;} for(i=2;i<=5;i++) for(j=1;j<=i-1;j++) a[i][j]=a[i-1][j]+a[i-1][j-1]; for(i=0;i<=5;i++){ for(j=0;j<=i;j++) printf("%4d",a[i][j]); printf("\n");}}7、/*經(jīng)過(guò)鍵盤輸入3名學(xué)生4門課程成績(jī)，分別求每個(gè)學(xué)生平均成績(jī)和每門課程平均成績(jī)。要求全部成績(jī)均放入一個(gè)4行5列數(shù)組中，輸入時(shí)同一人數(shù)據(jù)間用空格,不一樣人用回車其中最終一列和最終一行分別放每個(gè)學(xué)生平均成績(jī)、每門課程平均成績(jī)及班級(jí)總平均分。*/#include<stdio.h>#include<stdlib.h>intmain(){ floata[4][5],sum1,sum2; inti,j; for(i=0;i<3;i++) for(j=0;j<4;j++) scanf("%f",&a[i][j]); for(i=0;i<3;i++) { sum1=0; for(j=0;j<4;j++) sum1+=a[i][j]; a[i][4]=sum1/4; } for(j=0;j<5;j++) { sum2=0; for(i=0;i<3;i++) sum2+=a[i][j]; a[3][j]=sum2/3; } for(i=0;i<4;i++) { for(j=0;j<5;j++) printf("%6.2f",a[i][j]); printf("\n"); }}8、/*完善程序，實(shí)現(xiàn)將輸入字符串反序輸出，如輸入windows輸出swodniw。*/#include<string.h>#include<stdio.h>intmain(){ charc[200],c1; inti,j,k; printf("Enterastring:"); scanf("%s",c); k=strlen(c); for(i=0,j=k-1;i<k/2;i++,j--) {c1=c[i];c[i]=c[j];c[j]=c1;} printf("%s\n",c);}指針?lè)ǎ簐oidinvert(char*s){ inti,j,k; chart; k=strlen(s); for(i=0,j=k-1;i<k/2;i++,j--) {t=*(s+i);*(s+i)=*(s+j);*(s+j)=t;}}#include<stdio.h>intmain(){ FILE*fp; charstr[200],*p,i,j; if((fp=fopen("p9_2.out","w"))==NULL) { printf("cannotopenthefile\n"); exit(0);} printf("inputstr:\n"); gets(str); printf("\n%s",str); fprintf(fp,"%s",str); invert(str); printf("\n%s",str); fprintf(fp,"\n%s",str); fclose(fp);}9、/*下面程序功效是從字符數(shù)組s中刪除存放在c中字符。*/#include<stdio.h>intmain(){chars[80],c;intj,k;printf("\nEnterastring:");gets(s);printf("\nEnteracharacter:");c=getchar();for(j=k=0;s[j]!='\0';j++)if(s[j]!=c)s[k++]=s[j];s[k]='\0';printf("\n%s",s);}10、/*編寫一個(gè)voidsort(int*x,intn)實(shí)現(xiàn)將x數(shù)組中n個(gè)數(shù)據(jù)從大到小排序。n及數(shù)組元素在主函數(shù)中輸入。將結(jié)果顯示在屏幕上并輸出到文件out.dat中*/#include<stdio.h>voidsort(int*x,intn){ inti,j,k,t; for(i=0;i<n-1;i++) { k=i; for(j=i+1;j<n;j++) if(x[j]>x[k])k=j; if(k!=i){ t=x[i]; x[i]=x[k]; x[k]=t; } }}voidmain(){ FILE*fp; int*p,i,a[10]; fp=fopen("out.dat","w"); p=a; printf("Input10numbers:"); for(i=0;i<10;i++) scanf("%d",p++); p=a; sort(p,10); for(;p<a+10;p++) { printf("%d",*p); fprintf(fp,"%d",*p); }fclose(fp);}11、已知數(shù)組a中元素已按由小到大次序排列，以下程序功效是將輸入一個(gè)數(shù)插入數(shù)組a中，插入后，數(shù)組a中元素依然由小到大次序排列*/#include<stdio.h>intmain(){ inta[10]={0,12,17,20,25,28,30};intx,i,j=6;/*j為元素個(gè)數(shù)*/printf("Enteranumber:");scanf("%d",&x);a[0]=x;i=j;/*從最終一個(gè)單元開(kāi)始*/while(a[i]>x){a[i+1]=a[i];i--;}/*將比x大數(shù)往后移動(dòng)一個(gè)位置*/a[++i]=x;j++;/*插入x后元素總個(gè)數(shù)增加*/for(i=1;i<=j;i++)printf("%8d",a[i]);printf("\n");}12、/*編寫函數(shù)replace(char*s,charc1,charc2)實(shí)現(xiàn)將s所指向字符串中全部字符c1用c2替換，字符串、字符c1和c2均在主函數(shù)中輸入，將原始字符串和替換后字符串顯示在屏幕上，并輸出到文件p10_2.out中*/#include<stdio.h>replace(char*s,charc1,charc2){while(*s!='\0'){if(*s==c1)*s=c2;s++;}}intmain(){ FILE*fp; charstr[100],a,b; if((fp=fopen("p10_2.out","w"))==NULL){ printf("cannotopenthefile\n"); exit(0);} printf("Enterastring:\n"); gets(str); printf("Entera&&b:\n"); scanf("%c,%c",&a,&b); printf("%s\n",str); fprintf(fp,"%s\n",str); replace(str,a,b); printf("Thenewstringis----%s\n",str); fprintf(fp,"Thenewstringis----%s\n",str); fclose(fp); return0;}13、/*在一個(gè)字串s1中查找一子串s2，若存在則返回子串在主串中起始位置，不存在則返回-1。*/#include<stdio.h>intsearch(chars1[],chars2[]);intmain(){ chars1[6]="thisis";chars2[5]="is"; printf("%d\n",search(s1,s2));}intsearch(chars1[],chars2[]){ inti=0,j,len=strlen(s2); while(s1[i]) { for(j=0;j<len;j++) if(s1[i+j]!=s2[j])break; if(j>=len)returni; elsei++; } return-1;}14、/*用指針變量輸出結(jié)構(gòu)體數(shù)組元素。*/#include<stdio.h>structstudent{ intnum; char*name; charsex; intage;}stu[5]={{1001,"lihua",'F',18},{1002,"liuxing",'M',19},{1003,"huangke",'F',19},{1004,"fengshou",'F',19},{1005,"Wangming",'M',18}};intmain(){ inti; structstudent*ps; printf("Num\tName\t\t\tSex\tAge\t\n"); /*用指針變量輸出結(jié)構(gòu)體數(shù)組元素。*/ for(ps=stu;ps<stu+5;ps++) printf("%d\t%-10s\t\t%c\t%d\t\n",ps->num,ps->name,ps->sex,ps->age); /*用數(shù)組下標(biāo)法輸出結(jié)構(gòu)體數(shù)組元素學(xué)號(hào)和年紀(jì)。*/ for(i=0;i<5;i++) printf("%d\t%d\t\n",stu[i].num,stu[i].age);return0;}15、/*建立一個(gè)有三個(gè)結(jié)點(diǎn)簡(jiǎn)單鏈表：*/#include<stdio.h>#defineNULL0structstudent{ intnum; char*name; intage; structstudent*next;};intmain(){ structstudenta,b,c,*head,*p; a.num=1001; ="lihua"; a.age=18;/*對(duì)結(jié)點(diǎn)組員進(jìn)行賦值*/ b.num=1002; ="liuxing"; b.age=19; c.num=1003; ="huangke"; c.age=18; head=&a;/*建立鏈表，a為頭結(jié)點(diǎn)*/ a.next=&b; b.next=&c; c.next=NULL; p=head;/*輸出鏈表*/ do { printf("%5d,%s,%3d\n",p->num,p->name,p->age); p=p->next; }while(p!=NULL); return0;}16、/*輸入一個(gè)字符串，判斷其是否為回文。回文字符串是指從左到右讀和從右到左讀完全相同字符串。*/#include<stdio.h>#include<string.h>#include<string.h>intmain(){chars[100];inti,j,n;printf("輸入字符串：\n");gets(s);n=strlen(s);for(i=0,j=n-1;i<j;i++,j--)if(s[i]!=s[j])break;if(i>=j)printf("是回文串\n");elseprintf("不是回文串\n");}17、/*冒泡排序，從小到大，排序后結(jié)果輸出到屏幕及文件myf2.out*/#include<stdio.h>voidfun(inta[],intn){inti,j,t;for(i=0;i<=n-1;i++)for(j=0;j<i;j++)if(a[j]>a[j+1]){t=a[j];a[j]=a[j+1