第五周作业

1.调试分析课本每一个例题，有可能的话更改成2-3个方法的新程序；

2.编程实现课本每一个编程习题。

3. 编程定义一个4X5矩阵和5X3矩阵，并计算它们的积。

4.编程输出1到n的平方的自然数构成的“魔方阵”，魔方阵是指它每一行和每一列及对角线之和均相等的方阵。

5.积累调试程序经验，收集错误信息原因（每个同学收集3-5条错误信息原因，并输入电脑形成文字）。

例4.1

#include <iostream>using namespace std;int main(){int a[10],i;for(i=0;i<10;i++)a[i]=i*2+2;for(i=0;i<10;i++){cout<<a[i]<<"\t";if((i+1)%5==0)cout<<endl;}return 0;}

例4.2

#include <iostream>using namespace std;int main(){int i,math[100],n;float aver=0.0;int unpassedcount=0;int highscorecount=0;cout<<"请输入学生人数：";cin>>n;cout<<"请输入成绩：";for(i=0;i<n;i++){cin>>math[i];aver+=math[i];}aver/=n;for(i=0;i<n;i++){if(math[i]<60)unpassedcount++;if(math[i]>=90)highscorecount++;}cout<<"平均分："<<aver<<endl;cout<<"90分以上人数:"<<highscorecount<<endl;cout<<"不及格人数："<< unpassedcount<<endl;return 0;}

例4.3

#include <iostream>#include <iomanip>using namespace std;int main(){int a[5],i,j,k,t;cout<<"please input 5 numbers:"<<endl;for(i=0;i<5;i++)cin>>a[i];cout<<"the number are :";for(i=0;i<5;i++)cout<<setw(4)<<a[i];cout<<endl;for(i=0;i<4;i++)for(j=0;j<4-i;j++)if(a[j]>a[j+1]){t=a[j];a[j]=a[j+1];a[j+1]=t;}cout<<"the storted numbers are:";for(i=0;i<5;i++)cout<<setw(4)<<a[i];cout<<endl;return 0;}

例4.4

#include <iostream>#include <iomanip>using namespace std;int main(){int a[5],i,j,big;cout<<"please input 5numbers :"<<endl;for(i=0;i<5;i++)cin>>a[i];cout<<"the number are :";for(i=0;i<5;i++)cout<<setw(8)<<a[i];cout<<endl;big=a[0];for(i=1;i<5;i++)if(a[i]>big)   big=a[i];cout<<"the big number is :"<<big<<endl;return 0;}

例4.5

#include <iostream>#include <iomanip>using namespace std;int main(){int i,f[40]={1,1};for(i=2;i<40;i++)f[i]=f[i-2]+f[i-1];for(i=0;i<40;i++){if(i%4==0)cout<<endl;cout<<setw(12)<<f[i];}cout<<endl;return 0;}

例4.6

#include <iostream>#include <iomanip>using namespace std;int main(){int i,j,a[5][5];for(i=0;i<5;i++){for(j=0;j<5;j++){if(i%==0)a[i][j]=i*5+j+i;elsea[i][j]=i*5+j+i;}}for(i=0;i<5;i++){for(j=0;j<5;j++)cout<<setw(4)<<a[i][j];cout<<endl;}return 0;}

 例4.7

#include <iostream>#include <iomanip>using namespace std;int main(){int i,j,a[2][3],big;cout<<"please input the number"<<endl;for(i=0;i<2;i++){for(j=0;j<3;j++)cin>>a[i][j];}cout<<"the number are"<<endl;for(i=0;i<2;i++){for(j=0;j<3;j++)cout<<setw(4)<<a[i][j];cout<<endl;}big=a[0][0];for(i=0;i<2;i++){for(j=0;j<3;j++)if(a[i][j]>big)big=a[i][j];}cout<<setw(4)<<big<<setw (4)<<i<<setw(4)<<j<<endl;return 0;}

例4.8

#include <iostream>using namespace std;int main(){char str[50];cout<<"please input string:"<<endl;cin.get(str,50);cout<<"the string is :"<<endl;cout<<str<<endl;return 0;}

 

例4.9

#include <iostream>#include <cstring>using namespace std;int main(){char str[100];cout<<"请输入一个字符串:"<<endl;cin.get(str,100);cout<<"字符串为："<<str<<endl;cout<<"字符串"<<str<<"处理后的字符串为："<<endl;for(int i=strlen(str)-1;i>=0;i--)cout<<str[i];cout<<endl;return 0;}

例4.10
 

#include <iostream>#include <cstring>using namespace std;int main(){char str[50];cout<<"please input a string:";cin.get(str,50);cout<<"the length of string"<<str<<"is"<<strlen(str)<<endl;return 0;}

例4.12

#include <iostream>#include <cstring>using namespace std;int main(){char str[10];cout<<"请输入字符串，直到输入hello后程序结束："<<endl;do{cin>>str;}while (strcmp(str,"hello")!=0);return 0;}

 

例4.13

#include <iostream>using namespace std;int main(){char str[51];int len=0;cout<<"请输入一个字符串:"<<endl;cin.get(str,50);while(str[len]!='\0')len++;cout<<"字符串"<<str<<"的长度："<<len<<endl;return 0;}

课后习题：

习题1：

#include <iostream>using namespace std;int main(){int a[5],i,j,t;cout<<"please input the numbers:"<<endl;for(i=0;i<5;i++)cin>>a[i];cout<<"the  new numbers are:"<<endl;for(i=0;i<4;i++)for(j=0;j<4-i;j++)if(a[j]<a[j+1]){t=a[j];a[j]=a[j+1];a[j+1]=t;}for(i=0;i<5;i++)cout<<a[i]<<"    ";cout<<endl;return 0;}

习题二：和前面的重复了

习题三：

#include <iostream>#include <iomanip>using namespace std;int main(){int i,count=0,a[40]={1,1};cout<<"fibonacci数列为："<<endl;for(i=2;i<40;i++)a[i]=a[i-2]+a[i-1];for(i=0;i<40;i++){if(i%4==0)cout<<endl;cout<<setw(12)<<a[i];}cout<<endl;cout<<"第十六项为：";cout<<a[15];for(i=0;i<20;i++)if(a[i]>=100)count++;cout<<"三位数的个数为："<<count<<endl;return 0;}

习题四：

 

#include <iostream>#include <cstring>using namespace std;int main(){char str[100];cout<<"请输入一个字符串："<<endl;cin.get(str,100);cout<<"字符串"<<str<<"的长度为："<<strlen(str)<<endl;return 0;}

习题五：

 

#include <iostream>#include <cstring>using namespace std;int main(){char str[100];int len;cout<<"请输入一个字符串："<<endl;cin.get(str,100);len=strlen(str);cout<<"字符串的长度为："<<len<<endl;cout<<"方向输出后的字符串："<<endl;for(len;len>=0;len--)cout<<str[len];cout<<endl;return 0;}

 习题六：

#include <iostream>#include <cstring>using namespace std;int main(){char str[100],a[50],b[50];int i,j=0,k=0;for(i=0;i<100;i++){while(str[i]!='\0'){if(str[i]>='\0'&&str[i]<='\9'){a[j]=str[i];j++;}elseb[k]=str[i];k++;}}cout<<"处理后的字符串："<<endl;for(i=0;i<k;i++)cout<<b[i];cout<<"字符串的长度："<<endl;cout<<"len="<<strlen(b)<<endl;return 0;}

 

 

例5.6

 

#include <iostream>using namespace std;int max(int u,int v){int w;w=u>v?u:v;return w;}int main(){int a,b,c;cout<<"please input two numbers;"<<endl;cin>>a>>b;c=max(a,b);cout<<"max is "<<c<<endl;return 0;}

例5.7

 

#include <iostream>using namespace std;void swap(int u,int v);int main(){int a=4,b=4;cout<<"a="<<a<<"\tb="<<b<<endl;swap(a,b);cout<<"a="<<a<<"\tb="<<b<<endl;}void swap(int u,int v){int temp;temp=u;u=v;v=temp;}

 

例5.9

#include <iostream>using namespace std;void swap(int u,int v);int main(){int a=3,b=4;cout<<"a="<<a<<"\tb="<<b<<endl;swap(a,b);cout<<"a="<<a<<"\tb="<<b<<endl;return 0;}void swap(int &u,int &v){int temp;temp=u;u=v;v=temp;}