matlab字符串单元数组与结构体作业答案

1.编制一个脚本，查找给定字符串中指定字符出现的次数和位置；
str=['hopes,dreams,hold up,hold up'];
>> findstr(str,'o') %位置
ans =
2 15 23
>> a=findstr(str,'o');
n=length(a) %次数
n =
3
2．编写一个脚本，判断输入字符串中每个单词的首字母是否为大写，若不是则将其修改为大写，其他字母为小写。

>> str='i have a dream come true';
nlength=length(str);
for k=1:nlength
if (k==1 || isspace(str(k-1)))&&(str(k)<='z'&&str(k)>='a')
str(k)=char(double(str(k))-32);
end
end
disp(str);
I Have A Dream Come True
3．创建2×2 单元数组，第1、2 个元素为字符串，第三个元素为整型变量，第四个元素为双精度（double）类型，并将其用图形表示。

>> A=cell(2,2)
A(1,1)={'beijing'};
A(2,1)={'BEIJING'};
A(1,2)={uint8(5)};
A(2,2)={[1,2;4,7]}
cellplot(A)
A =
[] []
[] []
A =
'beijing' [ 5]
'BEIJING' [2x2 double]
4．创建一个结构体，用于统计学生的情况，包括学生的姓名、学号、各科成绩等。

然后使用该结构体对一个班级的学生成绩进行管理，如计算总分、平均分、排列名次等。

>>
student=struct('name',{'bam','mark','jimin'},'number',{1,2,3},'scores',{[75 ,89,82],[93,78,90],[85,62,77]} ,'subject',{'english,math,chinese','english, math,chinese','english,math,chinese'})
student =
1x3 struct array with fields:
name
number
scores
subject
>> student(1)
ans =
name: 'bam'
number: 1
scores: [75 89 82]
subject: 'english,math,chinese'
>> student(2)
ans =
name: 'mark'
number: 2
scores: [93 78 90]
subject: 'english,math,chinese' >> student(3)
ans =
name: 'jimin'
number: 3
scores: [85 62 77]
subject: 'english,math,chinese' >>
>> sum(student(1).scores)
ans =
246
>> sum(student(2).scores)
ans =
261
>> sum(student(3).scores)
ans =
224
mean(student(1).scores)
ans =
82
>> mean(student(2).scores)
ans =
87
>> mean(student(3).scores)
ans =
74.6667
>> [new,index]=sort([student.scores],'descend')
new =
93 90 89 85 82 78 77 75 62 index =
4 6 2 7 3
5 9 1 8 >> student(1).mean= mean(student(1).scores)
student(2).mean=mean(student(2).scores)
student(3).mean= mean(student(3).scores)
student =
1x3 struct array with fields:
name
number
scores
subject
mean
student =
1x3 struct array with fields:
name
number
scores
subject
mean
student =
1x3 struct array with fields:
name
number
scores
subject
mean
>> student(1)
ans =
name: 'bam'
number: 1
scores: [75 89 82]
subject: 'english,math,chinese'
mean: 82
>> student(2)
ans =
name: 'mark'
number: 2
scores: [93 78 90]
subject: 'english,math,chinese'
mean: 87
>> student(3)
ans =
name: 'jimin'
number: 3
scores: [85 62 77]
subject: 'english,math,chinese'
mean: 74.6667
>> [new,index]=sort([student.mean],'descend') new =
87.0000 82.0000 74.6667
index =
2 1 3。