武汉大学遥感院复试上机练习(节选)

1、现有一数组， 其元素值见文件test.txt ，要求通过编程的方法求出这组数中值最大的元素、值最小的元素和中值元素。结果通过编程的方法写入文本文件中输出。#include <iostream>#include <fstream>usingnamespace std;intmain()intnum;ifstreamfilein(if(!filein)cout <<"cannot open the file!"return0;filein >> num;int*data =new int num;for ( inti = 0; i

2、 < num; i+)filein >> datai;机试复习 2004testtest.txt");filein.close();intswap;for(inti = 0; i < num-1;i+)for(intj = i + 1; j < num; j+)if (datai>dataj)swap = datai; datai = dataj;dataj = swap;elsecontinue ;/ 冒泡法排序ofstream fileout(机试复习2004testtest2.txt");if(!fileout)cout <&

3、lt;"cannot open the file!"return0;fileout <<"max:" << datanum-1 << endl;fileout <<"min:"<< data0 << endl;fileout <<"medium:" << datanum/2 << endl;fileout.close();delete data,data=NULL;return1;编写调试程序从磁盘的数据文件

4、“SourceData.txt ”中读入 10000 个数据，先理解为125× 80的矩阵， 使用卷积矩阵1 进行卷积， 再理解为100×100 的矩阵， 使用卷积矩阵2 进行卷积。00100010012101511216210100121000100卷积矩阵1卷积矩阵2a11a12a1nb11b12b1ka21a22a2nb21b22b2 klkcijal ii , jkbijjii , jjii1 jj 122am1am2amnbl1bl 2blk例：由卷积模板B (3× 3)对 A 矩阵 (5×6)进行卷积得到结果矩阵Ca11a12a13a14a1

5、5a16a21a22a23a24a25a26a31a32a33a34a35a36b11b12b13a41a42a43a44a45a46b21b22b23a51a52a53a54a55a56b31b32b33BAC 中的元素 c33 为：c33a22 b11 a23 b12 a24 b13 a32 b21 a33 b22 a34 b23 a42 b31 a43 b32 a44 b33#include <iostream>#include <fstream>usingnamespace std;intmain()int*data =new int 10000;ifstrea

6、mfilein(机试复习 2005testSourceData.txt");if(!filein)cout <<"cannot open the file!"return0;for ( inti = 0; i < 10000; i+)filein >> datai;filein.close();intMat133 = 0, -1, 0, -1, 5, -1, 0, -1, 0 ;intMat255 = 0, 0, -1, 0, 0, 0, -1, -2, -1, 0, -1, -2, 16, -2, -1,0, -1, -2, -1,

7、 0, 0, 0, -1, 0, 0 ;intMatrix112580, MatrixNew112580 = 0 ;intMatrix2100100, MatrixNew2100100 = 0 ;intk = 0;for(inti = 0; i < 125; i+)for(intj = 0; j < 80; j+)Matrix1ij = datak;k+;k = 0;for ( inti = 0; i < 100; i+)for ( intj = 0; j < 100; j+)Matrix2ij = datak;k+;for ( inti = 1; i < 124

8、; i+)for ( intj = 1; j < 79; j+)for ( intm = -1; m <= 1; m+)for ( intn = -1; n <= 1; n+)MatrixNew1ij += Matrix1i + mj + n * Mat1m + 1n + 1;for ( inti = 2; i < 99; i+)for ( intj = 2; j < 99; j+)for ( intm = -2; m <= 2; m+)for ( intn = -2; n <= 2; n+)MatrixNew2ij += Matrix2i + mj

9、+ n * Mat2m + 2n + 2;ofstreamfileout(机试复习 2005testtest2.txt");if(!fileout)cout << "cannot open the file!"return0;for( inti = 1; i < 124; i+)for(intj = 1; j < 79; j+)fileout << MatrixNew1ij <<"" fileout << endl;fileout.close();delete data,data=NU

10、LL;return1;（ 1）利用随机函数rand()生成 (0， 1)区间的 100 个均匀分布随机数；提示： 首先利用“ srand(unsigned)time(NULL)”语句设置产生随机数的开始点（需要包含 time.h 头文件）；产生随机数的函数为 rand() ，为了将该随机数转换为（ 0， 1）围的数，利用“ rand()*1.0/RAND_MAX ”可实现此目的。（ 2）利用正态分布随机数的产生函数生成正态分布随机数。正态分布随机数生成函数如下：y2lnxcos2 x *0.3+1（ 3）计算出100 个正态分布随机数y 的均值和方差，计算公式如下：nnnxxi /n ，22/

11、 n) - (xi / n)2( xii1i 1i1其中，自变量x 即为 100 个均匀分布的随机数。#include<iostream>#include<fstream>#include<time.h>#include<cmath>#definePI 3.1415926using namespace std;int main()double *data = new double 100;srand(unsigned )time(NULL);for( inti = 0; i < 100; i+)datai = rand()*1.0 /RAN

12、D_MAX;double *data2 =new double 100;for ( inti = 0; i < 100; i+)data2i = 1 + 0.3*cos(2 *PI*datai)*sqrt(-2 * log(datai);double average = 0, variance = 0;for ( inti = 0; i < 100; i+)average += datai;variance += datai * datai;average /= 100;variance = variance/100 - average*average;/ 输出略delete da

13、ta, data =NULL;delete data2, data2 =NULL;return1;题目：已知某多光谱遥感影像一个样区的数据。 分别计算该样区数据的均值向量和协方差矩阵。计算公式如下 :1 N1mi1）均值向量 :N kxikT0M mm. m12n2）协方差矩阵:11121n21222 n式 中 :1N1( xik mi )( x jk mj )xik 表ijN kn1n2nn示第 i0个波段样区的第k 个像元值， N 为样区像元总个数。multispectral.h中：#include <iostream>#include <vector>usingn

14、amespace std;/=/ 计算多光谱影像每个波段的均值/average:输出每个波段的均值/num: 每个波段的像元总数/band: 每个波段的波段数/data:多光谱影像的像素值/=void Average( double *average,intnum,intband,vector <int > *data);/=/ 说明略/=void Matrix( vector <double > *matrix,double *average,vector <int > *data,intband, intnum);Multispectral.cpp中：#

15、include"multispectral.h"voidAverage(double * average , intnum, int band,vector<int> * data )for(inti = 0; i <band; i+)average i = 0;for(inti = 0; i <num; i+)for( int j = 0; j <band; j+)average j += ( double ) data ji /num; voidMatrix(vector <double > * matrix, double *

16、 average , vector<int > * data , int band, int num)for(inti = 0; i <band; i+)for(intj = 0; j <band; j+)matrix i.push_back(0);for(inti = 0; i <band; i+)for(intj = 0; j <band; j+)for ( intk = 0; k <num; k+)matrix ij += (double ) data ik -( double ) data jk -average i)*average j) /

17、num;主函数中：#include <iostream>#include <fstream>#include <vector>#include "multispectral.h"usingnamespace std;intmain()intband, num;ifstreamfilein(机试复习 2006data.txt"); / 判断略filein >> band;filein >> num;vector <int > *data= new vector<int >band;i

18、ntcount;for(inti = 0; i < band; i+)for(intj = 0; j < num; j+)filein >> count;datai.push_back(count);filein.close();double *average =new double band;vector <double > *matrix =new vector <double >num;Average(average, num, band, data);Matrix(matrix, average, data, band, num);del

19、ete data, data =NULL;delete matrix, matrix =NULL;delete average, average =NULL;/ 输出略 return 1;外包矩形的概念如下图所示：（点落在部和边缘上）用编制的程序判断哪些点落在矩形外包部，输出落在外包的点号。#include <iostream>#include <fstream>#include <vector>usingnamespace std;structPOINTdouble x; double y;POINT() memset( this , 0,sizeof (

20、 POINT); ;intmain()int num;ifstreamfilein(机试复习 2007test.txt");if(!filein)cout << "cannot open the file!"return 0;filein >> num;vector <POINT> data;POINTpoint;for( inti = 0; i < num; i+)filein >> point.x; filein >> point.y;data.push_back(point);filein.c

21、lose();double xmax = data0.x, xmin = data0.x, ymax = data0.y, ymin = data0.y;for(inti = 1; i < num; i+)if(datai.x>xmax)xmax = datai.x;if(datai.x<xmin)xmin = datai.x;if(datai.y>ymax)ymax = datai.y;if(datai.y<ymin)ymin = datai.y;cout <<"部点有： " ;for(inti = 0; i < num;

22、i+)if(datai.x != xmax&&datai.x != xmin&&datai.y != ymax&&datai.y != ymin)cout << i + 1 <<" " ;cout << endl;return1;程序改：（将判断点放在文件中，以点名（字符），x， y 方式储存）structPOINTJudgedouble x;double y;char name10;POINTJudge()x = 0.0;y = 0.0;ifstreamfilein2(机试复习 2007

23、外包矩形if(!filein2)cout <<"cannot open the file!"return0;vector <POINTJudge> record;while (!filein2.eof()POINTJudgejugde;filein2 >> >>jugde.x>>jugde.y;if(jugde.x < xmax&&jugde.x > xmin&&jugde.y < ymax&&jugde.y > ymin)

24、record.push_back(jugde);filein2.close();cout <<" 部点有： " ;for ( inti = 0; i < record.size(); i+)欲判断点 .dat");cout << <<""<< recordi.x <<" "<< recordi.y <<" " <<endl ;cout << endl;题目：编程统计某

25、专业的一门课程考试成绩的 最高分、最低分、平均分以及考试成绩分布的 均方差。说明：均方差计算公式如下：X ：考试成绩；N：成绩总个数#include <iostream>#include <cmath>#include <fstream>usingnamespace std;intmain()int num = 0;double max = 0, min = 100, sum1 = 0, sum2 = 0;ifstreamfilein(if(!filein)cout <<"cannot open the file!"retur

26、n1;filein >> num;double *data =new double num;for ( inti = 0; i < num; i+);新建文件夹2008年score.txt");filein >> datai;if(datai>max)max = datai;if(datai < min)min = datai;sum1 += datai;sum2 += datai * datai;filein.close();double average = 0.0, jun = 0.0;average = (double )sum1 /

27、num;jun = sqrt(double )sum2 / num - average*average);ofstream fp2(机试复习 2008result.txt");if(!fp2)cout <<"cannot open the file!"return0;fp2 <<" 最高分为 " << max << endl <<" 最低分为 " << min << endl;fp2 <<" 平均分为 " &l

28、t;< average << endl<<" 均方差为 " << jun << endl;fp2.close();delete data,data=NULL;return1;试题：文件 test.txt 中存贮了一串字符串， 请统计该文件中各字母出现的次数 （字母的大小写不加区分，如 a与A算同一字母，标点符号不统计） ，并按出现次数的多少由高到低进行排列输出 ，最后将字母及出现次数的排列写入 result.txt 文件中。#include <fstream>#include <iostream>

29、#include <vector>usingnamespace std;structalpint num; char d;alp() memset(this , 0,sizeof ( alp ); ;intmain()ifstreamfp(机试复习 2009source.txt"char data3000;/char *data =new char3000;intal26 = 0 ;intw = 0;);while (!fp.eof()dataw = fp.get();w+;fp.close();for( intj = 0; j < w; j+)if(dataj -

30、 65 >= 0 && dataj - 65 <= 25)aldataj - 65+;if(dataj - 97 >= 0 && dataj - 97 <= 25)aldataj - 97+;vector <alp > alph;alp me, ma;for( into = 0; o < 26; o+)me.d = 'A' + o; me.num = alo;alph.push_back(me);for ( inti = 0; i < 25; i+)for ( intj = i + 1; j <

31、; 26; j+)if (alphi.num>alphj.num)ma = alphi; alphi = alphj;alphj = ma;for ( into = 0; o < 26; o+)cout << alpho.d <<" "<< alpho.num << endl;/delete data,data=NULL; return 1;输出略题目：猫让 10 只老鼠站成一圈，它决定每数到第剩下的老鼠的位置n 只老鼠就吃掉，请输出最后<法一 >#include<stdio.h>#incl

32、ude<stdlib.h>void main()int i, j, id; int num, l;printf( " 请输入老鼠的个数： n" ); scanf( "%d", &num);printf( " 请输入间隔 ( 围：大于 0 且小于老鼠个数 ) ：n" ); scanf( "%d", &l);int*p;p = ( int*)malloc(sizeof ( int )*num);for (i = 0; i<num - 1; i+)pi = i + 1;pi = 0;for (i = 0, id = num - 1; i<num; i+)for (j = 0; j<l - 1; j+)id = pid;/ 往下数一位pid = ppid;/ 往下数两