#include "stdio.h"
int main(){int i,j,result;for (i=1;i<10;i++){ for(j=1;j<10;j++){result=i*j;printf("%d*%d=%-3d",i,j,result);/*-3d表示左对齐，占3位*/}printf("n");/*每一行后换行*/}}

#include "stdio.h"int main(){long f1,f2;int i;f1=f2=1;for(i=1;i<=20;i++){ printf("%12ld %12ld",f1,f2);if(i%2==0) printf("n");/*控制输出，每行四个*/f1=f1+f2; /*前两个月加起来赋值给第三个月*/f2=f1+f2; /*前两个月加起来赋值给第三个月*/}}

#include "math.h"#include "stdio.h"int main(){int m,i,k,h=0,leap=1;printf("n");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) /*内循环结束后，leap依然为1，则m是素数*/{printf("%-4d",m);h++;if(h%10==0)printf("n");}leap=1;}printf("nThe total is %d",h);}

#include "stdio.h"int main(){static int k[10];int i,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("%d is a wanshu: ",j);for(i=0;i<n;i++)printf("%d,",k[i]);printf("%dn",k[n]);}}}

#include <stdio.h>#include <string.h>void main(){ int a[4][4],b[4][4],i,j; /*a存放原始数组数据，b存放旋转后数组数据*/printf("input 16 numbers: ");/*输入一组数据存放到数组a中，然后旋转存放到b数组中*/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("array b:n");for(i=0;i<4;i++){ for(j=0;j<4;j++)printf("%6d",b[i][j]);printf("n");}}

#include <stdio.h>
void main(){int i,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");}}

#include <stdio.h>#include <stdlib.h>void main(){ float a[4][5],sum1,sum2;int i,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");}}

#include <string.h>#include <stdio.h>void main(){ char c[200],c1;int i,j,k;printf("Enter a string: ");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("%sn",c);}

#include <string.h>#include <stdio.h>void invert(char *s){int i,j,k;char t;k=strlen(s);for(i=0,j=k-1;i<k/2;i++,j--){ t=*(s+i); *(s+i)=*(s+j); *(s+j)=t; }}void main(){ FILE *fp;char str[200],*p,i,j;if((fp=fopen("p9_2.out","w"))==NULL){ printf("cannot open the filen");exit(0);}printf("input str:n");gets(str);printf("n%s",str);fprintf(fp,"%s",str);invert(str);printf("n%s",str);fprintf(fp,"n%s",str);fclose(fp);}

#include <stdio.h>void main(){
char s[80],c;int j,k;printf("nEnter a string: ");gets(s);printf("nEnter a character: ");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);}

#include<stdio.h>void sort(int *x,int n){int i,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;}}}void main(){FILE *fp;int *p,i,a[10];fp=fopen("p9_1.out","w");p=a;printf("Input 10 numbers:");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); }system("pause");fclose(fp);}

#include<stdio.h>void main(){ int a[10]={0,12,17,20,25,28,30}; /*a[0]为工作单元，从a[1]开始存放数据*/int x , i, j=6; /*j为元素个数*/printf("Enter a number: ");scanf("%d",&x);a[0]=x;i=j; /*从最后一个单元开始*/while(a[i]>x){ a[i+1]=a[i]; i--; } /*将比x大的数往后移动一个位置*/a[++i]=x;j++; /*插入x后元素总个数增加*/for(i=1;i<=j;i++) printf("%8d",a[i]);printf("n");}

#include<stdio.h>void replace(char *s,char c1,char c2){while(*s!='0'){ if (*s==c1)*s=c2;s++;}}void main(){ FILE *fp;char str[100],a,b;if((fp=fopen("p10_2.out","w"))==NULL){ printf("cannot open the filen");exit(0); }printf("Enter a string:n");gets(str);printf("Enter a&&b:n");scanf("%c,%c",&a,&b);printf("%sn",str);fprintf(fp,"%sn",str);replace(str,a,b);printf("The new string is----%sn",str);fprintf(fp,"The new string is----%sn",str);fclose(fp);}

#include<stdio.h>void replace(char *s,char c1,char c2)void main(){char s1[6]="thisis";char s2[5]="is";printf("%dn",search(s1,s2));system("pause");}int search(char s1[],char s2[]){int i=0,j,len=strlen(s2);while(s1[i]){for(j=0;j<len;j++)if(s1[i+j]!=s2[j]) break;if(j>=len)return i;else i++;}return -1;}

#include<stdio.h>struct student{int num;char *name;char sex;int age;}
stu[5]={{1001,"lihua",'F',18},{1002,"liuxing",'M',19},{1003,"huangke",'F',19},{1004,"fengshou",'F',19},{1005,"Wangming",'M',18}};void main(){int i;struct student *ps;printf("Num tNametttSextAgetn");/*用指针变量输出结构体数组元素。*/for(ps=stu;ps<stu+5;ps++)printf("%dt%-10stt%ct%dtn",ps->num,ps->name,ps->sex,ps->age);/*用数组下标法输出结构体数组元素学号和年龄。*/for(i=0;i<5;i++)printf("%dt%dtn",stu[i].num,stu[i].age);}

#include<stdio.h>#define NULL 0struct student{int num;char *name;int age ;struct student *next;};void main(){struct student a,b,c,*head,*p;a.num=1001; a.name="lihua"; a.age=18; /* 对结点成员进行赋值 */b.num=1002; b.name="liuxing"; b.age=19;c.num=1003; c.name="huangke"; c.age=18;head=&a; /* 建立链表，a为头结点 */a.next=&b;b.next=&c;c.next=NULL;p=head; /* 输出链表 */do{printf("%5d,%s,%3dn",p->num,p->name,p->age);p=p->next;}while(p!=NULL);}

#include <stdio.h>#include <string.h>
void main(){ char s[100];int i,j,n;printf("输入字符串：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");else printf("不是回文串n");}

#include<stdio.h>void fun(int a[],int n){int i,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];a[j+1]=t;}}void main(){int a[10]={12,45,7,8,96,4,10,48,2,46},n=10,i;FILE *f;if((f=fopen("myf2.out","w"))==NULL)printf("open file myf2.out failed!n");fun(a,10);for(i=0;i<10;i++){printf("%4d",a[i]);fprintf(f,"%4d",a[i]);}fclose(f);}

#include<stdio.h>double countpi(double eps) /*eps为允许误差*/{int m=1;double temp=1.0,s=0;while(temp>=eps){ s+=temp;temp=temp*m/(2*m+1);m++;}return(2*s);}void main(){FILE *fp;double eps=1e-5,pi;if((fp=fopen("p7_3.out","w"))==NULL){ printf("cannot open the filen");exit(0);}pi= countpi(eps);printf("pi=%lfn",pi);fprintf(fp,"pi=%lfn",pi);fclose(fp);}