c primer plus 习题答案(6)

p376.7

A方案

 1 #include<stdio.h>
 2 #include<stdlib.h>
 3 #define LEN 40
 4 void rank(FILE *, FILE *);
 5 int main(void)
 6 {
 7     FILE *fp, *fc;
 8     int ch, bp;
 9     char file1[LEN], file2[LEN];
10
11     puts("enter file1 name");
12     if((fp=fopen(gets(file1), "r"))==NULL){
13         fputs("can‘t open", stdout);
14         exit(1);
15     }
16
17     puts("enter file2 name");
18     if((fc=fopen(gets(file2), "r"))==NULL){
19         fputs("can‘t open", stdout);
20         exit(2);
21     }
22
23     rank(fp, fc);
24     if((fclose(fp)!=0)||(fclose(fc)!=0))
25         puts("error in closing files");
26
27     system("pause");
28     return 0;
29 }
30
31 void rank(FILE *fp, FILE *fc)
32 {
33     int ch, bp;
34     while(1){
35         while(((ch=getc(fp))!=‘\n‘)&&ch!=EOF)
36             putc(ch, stdout);
37         if(ch==‘\n‘)
38             putc(ch, stdout);
39         while(((bp=getc(fc))!=‘\n‘)&&bp!=EOF)
40             putc(bp, stdout);
41         if(ch==‘\n‘)
42             putc(bp, stdout);
43         if((ch==EOF)&&(bp==EOF))
44             break;
45     }
46 }

B方案

 1 #include<stdio.h>
 2 #include<stdlib.h>
 3 #define LEN 40
 4 void rank(FILE *, FILE *);
 5 int main(void)
 6 {
 7     FILE *fp, *fc;
 8     int ch, bp;
 9     char file1[LEN], file2[LEN];
10
11     puts("enter file1 name");
12     if((fp=fopen(gets(file1), "r"))==NULL){
13         fputs("can‘t open", stdout);
14         exit(1);
15     }
16
17     puts("enter file2 name");
18     if((fc=fopen(gets(file2), "r"))==NULL){
19         fputs("can‘t open", stdout);
20         exit(2);
21     }
22
23     rank(fp, fc);
24     if((fclose(fp)!=0)||(fclose(fc)!=0))
25         puts("error in closing files");
26
27     system("pause");
28     return 0;
29 }
30
31 void rank(FILE *fp, FILE *fc)
32 {
33     int ch, bp;
34     while(1){
35         while(((ch=getc(fp))!=‘\n‘)&&ch!=EOF)
36             putc(ch, stdout);
37         while(((bp=getc(fc))!=‘\n‘)&&bp!=EOF)
38             putc(bp, stdout);
39         if((bp==‘\n‘)||(ch==‘\n‘))
40             printf("\n");
41         if((ch==EOF)&&(bp==EOF))
42             break;
43     }
44 }

p376.8

 1 #include<stdio.h>
 2 #include<stdlib.h>
 3 #define LEN 40
 4 int main(int argc, char *argv[])
 5 {
 6     FILE *fp, *fc, *fd[LEN];
 7     char name1[LEN], name2[LEN];
 8     int ch, bp, count[2]={0}, i, num[LEN]={0};
 9     if(argc==2){
10         puts("enter file1 name");
11         if((fp=fopen(gets(name1), "r"))==NULL)
12             fputs("can‘t open", stderr);
13         puts("enter file1 name");
14         if((fc=fopen(gets(name2), "r"))==NULL)
15             fputs("can‘t open", stderr);
16
17         while((ch=getc(fp))!=EOF)
18             if(ch==argv[1][0])
19                 count[0]++;
20         while((bp=getc(fc))!=EOF)
21             if(bp==argv[1][0])
22                 count[1]++;
23
24         printf("%s has %d %c\n", name1, count[0], *argv[1]);
25         printf("%s has %d %c\n", name2, count[1], *argv[1]);
26     }
27
28     for(i=2; i<argc; i++){
29         if((fd[i]=fopen(argv[i], "r"))==NULL){
30             fputs("can‘t open\n", stderr);
31             continue;
32         }
33         while((ch=getc(fd[i]))!=EOF)
34             if(ch==*argv[1])
35                 num[i]++;
36         printf("%s has %d %c\n", argv[i], num[i], *argv[1]);
37     }
38
39     system("pause");
40     return 0;
41 }

p376.10

 1 #include<stdio.h>
 2 #include<stdlib.h>
 3 #define LEN 40
 4 int main(void)
 5 {
 6     FILE *fp;
 7     char name[LEN];
 8     long offset;
 9     int ch;
10
11     puts("enter the file name");
12     if((fp=fopen(gets(name), "r"))==NULL){
13         fprintf(stderr, "can‘t open\n");
14         exit(1);
15     }
16     puts("enter an offset of file(q to quit)");
17     while(scanf("%ld", &offset)==1){
18         fseek(fp, offset, SEEK_SET);
19         while(((ch=getc(fp))!=‘\n‘)&&ch!=EOF&&ch!=‘\r‘)
20             fprintf(stdout, "%c", ch);
21         if(ch==EOF)
22             exit;
23         printf("\n");
24         puts("enter an offset of file(q to quit)");
25     }
26
27     fclose(fp);
28     system("pause");
29     return 0;
30 }