1
2 /*Programming Exercise11-3*/
3 #include<stdio.h>
4 #define SIZE 20
5 char *getword(char *array,int len);
6 main()
7 {
8 char word[SIZE];
9 char *st;
10 st=getword(word,SIZE-1);
11 printf("%s\n",word);
12 }
13 char *getword(char *array,int len)
14 {
15 int c;
16 int i=0;
17 while((c=getchar())!=' '&&c!='\n'&&c!='\t'&&i< len)
18 {
19 *array++=c;
20 i++;
21 }
22 *array='\0';
23 return array;
24 }
25 /*1.数组已经通过参数传递，并且修改，所以打印还是用s作为printf的一个参数*/
26 /*2.对于字符数组，最重要的就是结束符。在需要时一定要手动添加*/
1
2 /*Programming Exercise11-2*/
3 #include<stdio.h>
4 #define SIZE 20
5 char *store(char *array,int len);
6 main()
7 {
8 char s[SIZE];
9 char *st;
10 st=store(s,SIZE-1);
11 printf("%s\n",s);
12 }
13 char *store(char *array,int len)
14 {
15 int c;
16 int i=0;
17 while((c=getchar())!=' '&&c!='\n'&&c!='\t'&&i< len)
18 {
19 *array++=c;
20 i++;
21 }
22 *array='\0';
23 return array;
24 }
1
2 /*Programming Exercise11-3*/
3 #include<stdio.h>
4 #define SIZE 20
5 char *getword(char *array,int len);
6 main()
7 {
8 char word[SIZE];
9 char *st;
10 st=getword(word,SIZE-1);
11 printf("%s\n",word);
12 }
13 char *getword(char *array,int len)
14 {
15 int c;
16 int i=0;
17 while((c=getchar())!=' '&&c!='\n'&&c!='\t'&&i< len)
18 {
19 *array++=c;
20 i++;
21 }
22 *array='\0';
23 return array;
24 }
1
2 /*Programming Exercise11-4*/
3 #include<stdio.h>
4 #define SIZE 20
5 char *search(char *array,int chr);
6 main()
7 {
8 char s[SIZE];
9 char *st;
10 char c;
11 gets(s);
12 while(1)
13 {
14 __fpurge(stdin);
15 printf("What char u wanna search?\n");
16 scanf("%c",&c);
17 st=search(s,c);
18 if(st==NULL)
19 printf("There is no %c in %s\n",c,s);
20 else
21 printf("%p\n",st);
22 }
23 }
24 char *search(char *array,int chr)
25 {
26 int i;
27 for(i=0;array[i]!='\0';i++)
28 if(array[i]==chr)
29 return array+i;
30 return NULL;
31 }
32 /*使用__fpurge(stdin)清空缓冲区的回车*/
1
2 /*Programming Exercise11-5*/
3 #include<stdio.h>
4 int is_within(char c,char *str);
5 main()
6 {
7 char s[100];
8 char c;
9 printf("Please input the string\n");
10 gets(s);
11 while(1)
12 {
13 printf("what char u wanna search?\n");
14 __fpurge(stdin);
15 c=getchar();
16 if(is_within(c,s))
17 printf("IN\n");
18 else
19 printf("NOT IN\n");
20 }
21 }
22 int is_within(char c,char *str)
23 {
24 int i;
25 while(*str!=c||*str!=EOF)
26 str++;
27 return *str;
28
29 }
30 /*使用__fpurge(stdin)清空缓冲区的回车*/
1
2 /*Programming Exercise11-6*/
3 #include<stdio.h>
4 char *Strncpy(char *s1,char *s2,int n);
5 main()
6 {
7 char s1[100],s2[100];
8 int n;
9 gets(s2);
10 printf("Please input n:\n");
11 scanf("%d",&n);
12 Strncpy(s1,s2,n);
13 puts(s1);
14 }
15 char *Strncpy(char *s1,char *s2,int n)
16 {
17 int i=0;
18 for(i=0;i < n;i++)
19 s1[i]=s2[i];
20 s1[i]='\0';
21
22 }
1
2 /*Programming Exercise11-7*/
3 #include<stdio.h>
4 #include<string.h>
5 char *string_in(const char *s1,const char *s2);
6 main()
7 {
8 char *ptr;
9 ptr=string_in("transportation","transportation");
10 if(ptr)
11 puts(ptr);
12 else
13 puts("Not found");
14 }
15 char *string_in(const char *s1,const char *s2)
16 {
17 int len1,len2;
18 int no=1;
19 int times;
20 len2=strlen(s2);
21 len1=strlen(s1);
22 times=len1-len2+1;
23 printf("%d %d\n",len1,len2);
24 if(times>0)
25 while(no=strncmp(s1,s2,len2)&×--)
26 s1++;
27 if(no)
28 return NULL;
29 else
30 return (char *) s1;
31 }
32 /*1.比较的次数自然要加1，否则当s1就是s2的时候会出现找不到*/
33 /*2.对s1进行自增运算，strncmp中的s1也就发生了变化*/
1
2 /*Programming Exercise11-8*/
3 #include<stdio.h>
4 #include<string.h>
5 void rev_string(char *s);
6 main()
7 {
8 char a[100];
9 gets(a);
10 rev_string(a);
11 puts(a);
12 }
13 void rev_string(char *s)
14 {
15 int i=0;
16 int len,temp;
17 len=strlen(s);
18 for(i=0;i < len/2;i++)
19 {
20 temp=s[i];
21 s[i]=s[len-1-i];
22 s[len-1-i]=temp;
23 }
24 }
25 /*1.不需要使用两个数组，一个数组就可以，也不需要指针*/
26 /*2.注意i<len/2，因为只需要把首尾对称的元素调换即可*/
1
2 /*Programming Exercise11-9*/
3 #include<stdio.h>
4 #include<string.h>
5 void no_space(char *s);
6 main()
7 {
8 char a[100];
9 gets(a);
10 no_space(a);
11 //puts(a);
12 }
13 void no_space(char *s)
14 {
15 int i;
16 int len;
17 char *pos;
18 char *start=s;
19 while(*s)
20 {
21 if(*s==' ')
22 {
23 pos=s;
24 do
25 {
26 *pos=*(pos+1);
27 pos++;
28 }while(*pos);
29 //printf("移动后结果：%s\n",start);
30 }
31 else
32 s++;
33 }
34 }
35 /*1.当有空格的时候，需要用后面的字符串覆盖前面字符串*/
36 /*2.当遇到空格时候，用新的指针pos指向当前位置，然后不断用后面字符覆盖前面*/
37 /*3.while(*pos)表明了，当遇到空格，后面覆盖前面是到字符串最终结尾为止的*/
38 /*4.相当于空格后面的字符串整体前移*/
1
2 /*Programming Exercise11-10*/
3 #include<stdio.h>
4 #include<string.h>
5 #define MAXLINES 10
6 #define MAXLEN 100
7 #define ALLOCSIZE 1000
8 int Readlines(char *lineptr[],int nlines);
9 void Writelines(char *lineptr[],int nlines);
10 void qsort(void *v[],int left,int right,int (*comp)(void *,void *));
11 void as_order(char *lineptr[],int lines);
12 void s2l_order(char *lineptr[],int lines);
13 void word_order(char *lineptr[],int lines);
14 main()
15 {
16 char *list[MAXLINES];
17 int flag=1;
18 int n,lines;
19 printf("----------------------------------------------\n\n");
20 printf(" * Please input 10 strings\n");
21 while((lines=Readlines(list,MAXLINES))<=0)//括号要有，赋值优先级低
22 printf("Please input 10 strings\n");
23 printf("\n* Input succeed!\n");
24 printf("* U have input %d lines\n",lines);
25 printf("\n----------------------------------------------\n");
26 printf("1.按初始顺序输出\t2.按ASCII顺序输出\n");
27 printf("3.按长度递增顺序输出\t4.按首单词长度顺序输出\n");
28 printf("q.退出\n");
29 printf("----------------------------------------------\n");
30 __fpurge(stdin);
31 printf("PLease chose ur function\n");
32 flag=scanf("%d",&n);
33 while(flag==1)
34 {
35 switch(n)
36 {
37 case 1:
38 printf("按初始顺序输出:\n");
39 Writelines(list,lines);
40 break;
41 case 2:
42 printf("按ASCII顺序输出:\n");
43 as_order(list,lines);
44 break;
45 case 3:
46 printf("按长度递增顺序输出:\n");
47 s2l_order(list,lines);
48 break;
49 case 4:
50 printf("按首单词长度顺序输出:\n");
51 word_order(list,lines);
52 break;
53 default:
54 printf("\nError:You should choose from the table!\n");
55 break;
56 }
57 printf("----------------------------------------------\n");
58 printf("PLease chose ur function\n");
59 flag=scanf("%d",&n);
60 }
61 }
62
63 int Getline(char line[],int maxline);//读入字符串函数
64 char *alloc(int);//储存空间分配函数
65 int Readlines(char *lineptr[],int maxlines)
66 {
67 int len;
68 int nlines;
69 char *p;//永久储存空间的字符串指针
70 char line[MAXLEN];
71 nlines=0;
72 while((len=Getline(line,MAXLEN))>0)
73 if(nlines>=maxlines||(p=alloc(len))==NULL)
74 return -1;//不做小于10行的判断，只规定不能超过10行
75 else
76 {
77 line[len-1]='\0'; //删除换行符
78 strcpy(p,line); //把临时空间line中字符串复制到永久空间
79 lineptr[nlines++]=p;//储存指针地址
80 }
81 return nlines;//允许小于10行的任意行输出
82
83 }
84 int Getline(char s[],int lim)
85 {
86 int c,i;
87 for(i=0;i<(lim-1)&&(c=getchar())!=EOF&&c!='\n';i++)
88 s[i]=c;
89 if(c=='\n')
90 {
91 s[i]=c;
92 ++i;
93 }
94 s[i]='\0';
95 return i;
96 }
97 void Writelines(char *lineptr[],int nlines)
98 {
99 while(nlines-->0)
100 {
101 printf("%s\n",*lineptr++);
102 }
103
104 }
105 static char allocbuf[ALLOCSIZE];//永久储存空间
106 static char *allocp=allocbuf;
107 char *alloc(int n)
108 {
109 if(allocbuf+ALLOCSIZE-allocp>=n)
110 {
111 allocp+=n;
112 return allocp-n;
113 }
114 else
115 return 0;
116 }
117 void qsort(void *v[],int left,int right,int (*comp)(void *,void *))
118 {
119 int i,last;
120 void swap(void *v[],int i,int j);
121 if(left>=right)
122 return ;
123 swap(v,left,(left+right)/2);
124 last=left;
125 for(i=left+1;i<=right;i++)
126 if((*comp)(v[i],v[left])<0)
127 swap(v,++last,i);
128 swap(v,left,last);
129 qsort(v,left,last-1,comp);
130 qsort(v,last+1,right,comp);
131 }
132 int lencmp(char v1[],char v2[])
133 {
134 int len1,len2;
135 len1=strlen(v1);
136 len2=strlen(v2);
137 if(len1>len2)
138 return 1;
139 else if(len1< len2)
140 return -1;
141 else
142 return 0;
143 }
144 int wordcmp(char v1[],char v2[])
145 {
146 int i,j;
147 i=j=0;
148 while(v1[i]!=' ')
149 i++;
150 while(v2[j]!=' ')
151 j++;
152 if(i>j)
153 return 1;
154 else if(i< j)
155 return -1;
156 else
157 return 0;
158 }
159 void swap(void *v[],int i,int j)
160 {
161 void *temp;
162 temp=v[i];
163 v[i]=v[j];
164 v[j]=temp;
165 }
166 void s2l_order(char *lineptr[],int lines)
167 {
168 qsort((void **)lineptr,0,lines-1,(int (*)(void *,void *))(lencmp));
169 Writelines(lineptr,lines);
170 }
171 void word_order(char *lineptr[],int lines)
172 {
173 qsort((void **)lineptr,0,lines-1,(int (*)(void *,void *))(wordcmp));
174 Writelines(lineptr,lines);
175 }
176 void as_order(char *lineptr[],int lines)
177 {
178 qsort((void **)lineptr,0,lines-1,(int (*)(void *,void *))(strcmp));
179 Writelines(lineptr,lines);
180 }
1
2 /*Programming Exercise11-11*/
3 #include<stdio.h>
4 #include<ctype.h>
5 int word_count(char *s);
6 int upper_count(char *s);
7 int lower_count(char *s);
8 int punct_count(char *s);
9 int digit_count(char *s);
10 int isword(char *s);
11 #define SIZE 100
12 main()
13 {
14 int c;
15 char s[SIZE];
16 int i=0;
17 int nword,nupper,nlower,npunct,ndigit;
18 nword=nupper=nlower=npunct=ndigit=0;
19 printf("Please input a string\n");
20 while((c=getchar())!=EOF&&c!='\n')
21 {
22 s[i]=c;
23 i++;
24 }
25 s[i]='\0';
26 printf("输入的字符串：%s\n",s);
27 nword=word_count(s);
28 nupper=upper_count(s);
29 nlower=lower_count(s);
30 npunct=punct_count(s);
31 ndigit=digit_count(s);
32 printf("words:%d\n",nword);
33 printf("upper-case:%d\n",nupper);
34 printf("lower-case:%d\n",nlower);
35 printf("punctuation:%d\n",npunct);
36 printf("digit:%d\n",ndigit);
37 }
38 #define OUT 0
39 #define IN 1
40 int word_count(char *s)
41 {
42 int i=0;
43 int count=0;
44 int state=OUT;
45 while(s[i]!='\0'&&s[i]==' ')
46 i++;
47 while(s[i]!='\0')
48 {
49 if((ispunct(s[i])&&s[i]!='-')||isblank(s[i])||s[i]=='\n')
50 state=OUT;
51 else if(state==OUT&&!isdigit(s[i]))
52 {
53 state=IN;
54 count++;
55 }
56 i++;
57 }
58 return count;
59 }
60 int upper_count(char *s)
61 {
62 int i=0;
63 int count=0;
64 while(s[i]!='\0')
65 {
66 if(isupper(s[i]))
67 count++;
68 i++;
69 }
70 return count;
71 }
72 int lower_count(char *s)
73 {
74 int i=0;
75 int count=0;
76 while(s[i]!='\0')
77 {
78 if(islower(s[i]))
79 count++;
80 i++;
81 }
82 return count;
83 }
84 int punct_count(char *s)
85 {
86 int i=0;
87 int count=0;
88 while(s[i]!='\0')
89 {
90 if(ispunct(s[i]))
91 count++;
92 i++;
93 }
94 return count;
95 }
96 int digit_count(char *s)
97 {
98 int i=0;
99 int count=0;
100 while(s[i]!='\0')
101 {
102 if(isdigit(s[i]))
103 count++;
104 i++;
105 }
106 return count;
107 }
1
2 /*Programming Exercise11-12*/
3 #include<stdio.h>
4 int main(int argc,char *argv[])
5 {
6 int i=argc;
7 while(i-->1)
8 argv++;//首先把指针移动到倒数第二个位置
9 while(argc-->1)
10 printf("%s ",*argv--);//逆序打印但是不能打印argv[0]
11 printf("\n");
12 }
1
2 /*Programming Exercise11-13*/
3 #include<stdio.h>
4 #include<stdlib.h>
5 int main(int argc,char *argv[])
6 {
7 double base,power,temp=1,result=1;//必须有初值
8 base=atof(argv[1]);
9 power=atof(argv[2]);
10 if(power==0)
11 result=1;
12 else if(power<0)
13 {
14 power=-power;//为了递减，需要变成正数
15 while(power-->0)
16 temp*=base;
17 result=1/temp;
18 }
19 else
20 while(power-->0)
21 result*=base;
22 printf("%.3f^%.3f=%.3f\n",base,power,result);
23 }
1
2 /*Programming Exercise11-14*/
3 #include<stdio.h>
4 #include<ctype.h>
5 #define SIZE 100
6 int myatoi(char *s);
7 main()
8 {
9 int num,c,i=0;
10 char s[SIZE];
11 printf("Please input a string\n");
12 while((c=getchar())!='\n')
13 {
14 s[i]=c;
15 i++;
16 }
17 s[i]='\0';
18 printf("the int number: \n");
19 if(num=myatoi(s))
20 printf("%d\n",num);
21 else
22 printf("the string is not a int number!\n");
23 }
24 int myatoi(char *s)
25 {
26 int sign=1;
27 int i=0;
28 int n=0;
29 if(s[i]=='-')
30 {
31 sign=-1;
32 i++;//只有当s[0]是负号的时候才跳过
33 }
34 else
35 sign=1;//否则仍让从s[0]开始
36 while(s[i]!='\0')
37 {
38 if(isdigit(s[i]))
39 {
40 n=n*10+s[i]-'0';
41 }
42 else
43 return 0;
44 i++;
45 }
46 return n*sign;
47 }
1
2 /*Programming Exercise11-15*/
3 #include<stdio.h>
4 #include<ctype.h>
5 #define SIZE 1000
6 int main(int argc,char *argv[])
7 {
8 int c,i=0;
9 char s[SIZE];
10 char *p;
11 while((c=getchar())!=EOF)
12 {
13 s[i]=c;
14 i++;
15 }
16 s[i]='\0';
17 p=s;
18 //printf("%c %c\n",*argv[1],*(argv[1]+1));
19 if(argc>1&&*argv[1]=='-')
20 {
21 if(*(argv[1]+1)=='p')
22 {
23 printf("按照原样输出：\n");
24 while(*p!='\0')
25 putchar(*p++);
26 }
27 else if(*(argv[1]+1)=='u')
28 {
29 printf("全部转换为大写字母：\n");
30 while(*p!='\0')
31 putchar(toupper(*p++));
32 }
33 else if(*(argv[1]+1)=='l')
34 {
35 printf("全部转换为大写字母：\n");
36 while(*p!='\0')
37 putchar(tolower(*p++));
38 }
39 else
40 printf("Only -p,-l,-u please!\n");
41 }
42 else
43 printf("请输入命令行参数-p,-l,-u\n");
44 }
