编程环境Visual Studio 2017
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#include <stdio.h> #include <stdlib.h> #include <math.h> #include <string.h> #include <memory.h> #include <ctype.h> // practice 1 int p13_1(void) { int ch; FILE *fp; unsigned long count = 0; char file_name[256]; printf("Enter the file name: "); scanf_s("%s", file_name, 256); if ((fp = fopen(file_name, "r")) == NULL) // fopen函数在VS2017中报告会报错，解决办法是在 项目 =》属性 =》c/c++ =》预处理器=》点击预处理器定义，编辑，加入_CRT_SECURE_NO_WARNINGS { // scanf_s之类的安全增强函数应该也适用(具体还没有试过)，早知道就百度查一下了，之前使用的都是scanf_s printf("Can't not open %s\n", file_name); } while ((ch = getc(fp)) != EOF) { putc(ch, stdout); count++; } fclose(fp); printf("File %s has %lu characters\n", file_name, count); return 0; } // practice 2 void p13_2(void) { FILE *fp1; FILE *fp2; char *file1 = "data1.dat"; char *file2 = "data2.dat"; int ch = 0; if ((fp1 = fopen(file1, "rb")) == NULL) { printf("Can't open %s\n", file1); } if ((fp2 = fopen(file2, "wb")) == NULL) { printf("Can't open %s\n", file2); } while ((ch = fgetc(fp1)) != EOF) { fputc(ch, fp2);; } fclose(fp1); fclose(fp2); return; } //practice 3 void p13_3(void) { char file_name[256]; char *tmp_file = "tmp.txt"; // 现在只能想到把读出来的数据保存到一个缓存文件里，然后再从缓存文件度回，暂时没想到同时读取修改同一个文件的方法 int ch = 0; FILE *fp_r; FILE *fp_w; printf("Enter the file name: "); gets_s(file_name, 256); if ((fp_r = fopen(file_name, "r+")) == NULL) { printf("Can't open %s as read mode!\n", file_name); } if ((fp_w = fopen(tmp_file, "w")) == NULL) { printf("Can't open %s as write mode!\n", tmp_file); } while ((ch = fgetc(fp_r)) != EOF) { ch = toupper(ch); fputc(ch, fp_w); } fclose(fp_r); fclose(fp_w); if ((fp_r = fopen(tmp_file, "r")) == NULL) { printf("Can't open %s as read!\n", tmp_file); } if ((fp_w = fopen(file_name, "w")) == NULL) { printf("Can't open %s as write!\n", file_name); } while ((ch = fgetc(fp_r)) != EOF) { fputc(ch, fp_w); } fclose(fp_r); fclose(fp_w); remove(tmp_file); printf("Done.\n"); return; } // practice 4 int p13_4(int argc, char **argv) { FILE *fp; char buf[256] = { 0 }; for (int i = 1; i < argc; i++) { if ((fp = fopen(argv[i], "r")) == NULL) { printf("Can't open file %s as read!\n", argv[i]); } printf("%s:\n", argv[i]); while (fgets(buf, 256, fp) != NULL) { fputs(buf, stdout); } printf("\n"); } printf("Done!\n"); return 0; } // practice 5 #define BUFFSIZE 4096 #define SLEN 81 void append(FILE *source, FILE *dest) { size_t bytes; static char temp[BUFFSIZE]; while ((bytes = fread(temp, sizeof(char), BUFFSIZE, source)) > 0) { fwrite(temp, sizeof(char), bytes, dest); } } char *s_gets(char *st, int n) { char *ret_val; char *find; ret_val = fgets(st, n, stdin); if (ret_val) { find = strchr(st, '\n'); if (find) { *find = '\0'; } else { while (getchar() != '\n') { continue; } } } return ret_val; } void p13_5(int argc, char **argv) { FILE *fa, *fs; int files = 0; int ch; if (argc <3) { printf("Usage: %s dest_file source1_file ...\n", argv[0]); return; } if ((fa = fopen(argv[1], "a+")) == NULL) { fprintf(stderr, "Can't open %s\n", argv[1]); exit(EXIT_FAILURE); } if (setvbuf(fa, NULL, _IOFBF, BUFFSIZE) != 0) { fputs("Can't create output buffer\n", stderr); exit(EXIT_FAILURE); } for (int i = 2; i < argc; i++) { if (strcmp(argv[1], argv[i]) == 0) { fputs("Can't append file to itself\n", stderr); } else if ((fs = fopen(argv[i], "r")) == NULL) { fprintf(stderr, "Can't open %s\n", argv[i]); } else { if (setvbuf(fs, NULL, _IOFBF, BUFFSIZE) != 0) { fputs("Can't create input buffer\n", stderr); continue; } append(fs, fa); if (ferror(fs) != 0) { fprintf(stderr, "Error in reading file %s.\n", argv[i]); } if (ferror(fa) != 0) { fprintf(stderr, "Error in writing file %s.n", argv[1]); } fclose(fs); files++; printf("File %s appended.\n", argv[i]); } } printf("Done appending. %d files appended.\n", files); rewind(fa); printf("%s contents:\n", argv[1]); while ((ch = getc(fa)) != EOF) { putchar(ch); } puts("Done displaying!\n"); fclose(fa); return; } // practice 6 #define LEN 40 void p13_6(void) { FILE *in, *out; int ch; char out_file[LEN]; char in_file[LEN]; int count = 0; printf("Enter the file name:"); gets_s(in_file, LEN); if ((in = fopen(in_file, "r")) == NULL) { fprintf(stderr, "I couldn't open the file\"%s\"", in_file); exit(EXIT_FAILURE); } strncpy(out_file, in_file, LEN-5); out_file[LEN - 5] = '\0'; strcat(out_file, ".red"); if ((out = fopen(out_file, "w")) == NULL) { fprintf(stderr, "Can't creat output file.\n"); exit(3); } while ((ch = getc(in)) != EOF) { if (count++ % 3 == 0) putc(ch, out); } if (fclose(in) != 0 || fclose(out) != 0) { fprintf(stderr, "Error in closing files\n"); } return; } // practice 7 void p13_7(void) { FILE *file1, *file2; char file_name1[128]; char file_name2[128]; char buf1[256] = { 0 }; char buf2[256] = { 0 }; printf("Enter the first file name:"); gets_s(file_name1, 128); printf("Enter the second file name:"); gets_s(file_name2, 128); if ((file1 = fopen(file_name1, "r")) == NULL) { printf("Can't open %s\n", file_name1); } if ((file2 = fopen(file_name2, "r")) == NULL) { printf("Can't open %s\n", file_name2); } while ((feof(file1) == 0) || (feof(file2) == 0)) { if (fgets(buf1, 256, file1) != NULL) { int length = strlen(buf1); // 要实现B情况，添加如下代码 /* if (buf1[length - 1] == '\n') { buf1[length - 1] = '\0'; } */ fputs(buf1, stdout); } if (fgets(buf2, 256, file2) != NULL) { fputs(buf2, stdout); } } return; } // practice 8 void p13_8(int argc, char **argv) { char find_ch = 0; char ch = 0; char input[256] = { 0 }; int repeat_time = 0; FILE *fp; if (argc < 2) { printf("Usage: %s <character> [file_name1 ....]", argv[0]); return; } find_ch = argv[1][0]; if (argc == 2) { printf("Enter the string you wanted to analysize: "); gets_s(input, 256); int input_length = strlen(input); for (int i = 0; i < input_length; i++) { if (find_ch == input[i]) { repeat_time++; } } printf("In string \"%s\", %c have appeared %d times!\n", input, find_ch, repeat_time); } else { for (int i = 2; i < argc; i++) { repeat_time = 0; if ((fp = fopen(argv[i], "r")) == NULL) { printf("Can't open %s\n", argv[i]); continue; } while ((ch = fgetc(fp)) != EOF) { if (ch == find_ch) { repeat_time++; } } printf("In file %s, %c have appeared %d time!\n", argv[i], find_ch, repeat_time); } } return; } // practice 9 // 暂时的想到的解决办法是将单词读出来获取前面的标号，但是这样好像不够优雅 #define MAX 41 void p13_9(void) { FILE *fp; char words[MAX]; int n_word = 0; if ((fp = fopen("wordy", "a+")) == NULL) { fprintf(stdout, "Can't open\"wordy\" file.\n"); exit(EXIT_FAILURE); } rewind(fp); while (fgets(words, MAX, fp) != NULL) { n_word++; } puts("Enter words to add to the file; press the #"); puts("key at the begining of a line to terminate."); while ((fscanf(stdin, "%40s", words) == 1) && (words[0] != '#')) { fprintf(fp, "%d:%s\n", ++n_word, words); } puts("File contents:"); rewind(fp); while (fscanf(fp, "%s", words) == 1) { puts(words); } puts("Done"); if (fclose(fp) != 0) { fprintf(stderr, "Error closing file\n"); } return; } // practice 10 void p13_10(void) { char file_name[256]; char content[256]; int file_seek = 0; FILE *fp; printf("Enter the file name:"); fscanf(stdin, "%s", file_name); // scanf("%s", file_name); if ((fp = fopen(file_name, "r")) == NULL) { printf("Can't open %s file.\n", file_name); } while (1) { printf("Enter the location of file to print ( <0 to terminate) :"); if (fscanf(stdin, "%d", &file_seek) != 1 || file_seek < 0) { break; } fseek(fp, file_seek, SEEK_SET); fgets(content, 256, fp); // fscanf(fp, "%s", content); // 奇怪，下面这两个打印方法都没有办法打印 (好吧，我知道了，我这是输出啊，应该用的是stdout，汗....) // fprintf(stdin, "%s", content); // fputs(content, stdin); printf("%s", content); } puts("Done"); fclose(fp); return; } // practice 11 void p13_11(int argc, char **argv) { char content[256]; FILE *fp; if (argc != 3) { printf("Usage: %s <string> <file_name>\n", argv[0]); exit(EXIT_FAILURE); } if ((fp = fopen(argv[2], "r")) == NULL) { printf("Can't open file %s.\n", argv[2]); } while ((fgets(content, 256, fp)) != NULL) { if (strstr(content, argv[1]) != NULL) { fputs(content, stdout); } } } // practice 12，13，14 // 剩下的就不写了，那个数组600个数字，全部输完都成斗鸡眼了 int main(int argc, char **argv) { // p13_10(); p13_11(argc, argv); while (getchar()); return 0; } |
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关于12题可以用随机函数 生成数字存在文档里
#include
#include
int main()
{
FILE *p;
p=fopen("F:\\data2.txt","w");
for(int i=0;i<600;i++)
{
fprintf(p,"%-5d",rand()%10);
if((i+1)%30==0)
{
fprintf(p,"%-5d\n",rand()%10);
}
}
fclose(p);
return 0;
}
第9题我是查找每行开头的序号然后获取序号，比你这直接计算行数蠢多了。。。
0 0 9 0 0 0 0 0 0 0 0 0 5 8 9 9 8 5 2 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 9 0 0 0 0 0 0 0 5 8 9 9 8 5 5 2 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 5 8 1 9 8 5 4 5 2 0 0 0 0 0 0 0 0 0
0 0 0 0 9 0 0 0 0 0 0 0 5 8 9 9 8 5 0 4 5 2 0 0 0 0 0 0 0 0
0 0 9 0 0 0 0 0 0 0 0 0 5 8 9 9 8 5 0 0 4 5 2 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 5 8 9 1 8 5 0 0 0 4 5 2 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 5 8 9 9 8 5 0 0 0 0 4 5 2 0 0 0 0 0
5 5 5 5 5 5 5 5 5 5 5 5 5 8 9 9 8 5 5 5 5 5 5 5 5 5 5 5 5 5
8 8 8 8 8 8 8 8 8 8 8 8 5 8 9 9 8 5 8 8 8 8 8 8 8 8 8 8 8 8
9 9 9 9 0 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 3 9 9 9 9 9 9 9
8 8 8 8 8 8 8 8 8 8 8 8 5 8 9 9 8 5 8 8 8 8 8 8 8 8 8 8 8 8
5 5 5 5 5 5 5 5 5 5 5 5 5 8 9 9 8 5 5 5 5 5 5 5 5 5 5 5 5 5
0 0 0 0 0 0 0 0 0 0 0 0 5 8 9 9 8 5 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 5 8 9 9 8 5 0 0 0 0 6 6 0 0 0 0 0 0
0 0 0 0 2 2 0 0 0 0 0 0 5 8 9 9 8 5 0 0 5 6 0 0 6 5 0 0 0 0
0 0 0 0 3 3 0 0 0 0 0 0 5 8 9 9 8 5 0 5 6 1 1 1 1 6 5 0 0 0
0 0 0 0 4 4 0 0 0 0 0 0 5 8 9 9 8 5 0 0 5 6 0 0 6 5 0 0 0 0
0 0 0 0 5 5 0 0 0 0 0 0 5 8 9 9 8 5 0 0 0 0 6 6 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 5 8 9 9 8 5 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 5 8 9 9 8 5 0 0 0 0 0 0 0 0 0 0 0 0
帮你贴过来了，不用谢
好人一生平安
哈哈 就是来找它的！ 感谢！
好人一生平安，就是来找它的
第7题的B，要是文件1比2大后面的每行不就全部在一起了吗
第二题运行时会出现Debug Assertion Failed ，返回can’t open是怎么回事 ????
是不是文件打开失败了？确定文件存在吗？
第7题，关于添加代码实现 B 的内容，
如果是分步进行的话，应该要再添加两个rewind()，
但如果是同步进行，演示效果会不会受影响呢？
第7题 关于添加代码以实现 B 的内容，
如果分步执行 A ，B，应该添加两个rewind()，
但如果同步执行，演示效果是否会受影响呢？
你可以试一下，我这边没有试过这种情况
第三题 可以用用两个文件指针打开同一个文件，一个读，一个写。 也可以用一个文件指针同时读写，但是要在每次写入之前设置文件位置指针fseek(fp, -1, SEEK_CUR), 写入之后要重新设置指针到当前位置 fseek(fp, 0, SEEK_CUR)。
你有试过这种方法吗？我当时有试过这样做，但是貌似以写的方式打开的话会将文件清空
兄dei，这种方法你试过吗？用写打开文件直接清空了呀，麻烦指教一下
char *tmp_file = "tmp.txt";这行代码晒什么意思呢？求解答
第九题用 fseek() 移动光标获取文件最后一个单词的编号，然后用 atoi() 将编号转为数值。（编程环境: gcc 版本 9.3.0 (Arch Linux 9.3.0-1)）
#include
#include
#include
#include
#define MAX 41
#define LIMIT 1024 //单词编号上限
int main(void)
{
FILE *fp; //指向目标文件
char words[MAX]; //单词最大字符数
int num = 0; //单词编号
char num_s[LIMIT]; //单词编号字符串，方便调用atoi()函数
long len = 0; //文件长度
char ch; //存储从文件中读取字符
int i; //计数器
char temp; //临时存储字符
if ((fp = fopen("wordy", "ab+")) == NULL)
{
fprintf(stderr, "Can't open \"wordy\" file.\n");
exit(EXIT_FAILURE);
}
fseek(fp, 0L, SEEK_END); //光标定位到文件末尾
len = ftell(fp);
for (long count = 1; count < len; count++)
{ //获取打开的文件中最末尾单词的标号
fseek(fp, -count, SEEK_END); //光标回退
ch = getc(fp);
if (ch == ']')
i = 0;
if (isdigit(ch))
num_s[i++] = ch;
if (ch == '[')
break;
}
for (int j = 0; j < i / 2; j++)
{ //将倒置的单词编号调整为正确值
temp = num_s[j];
num_s[j] = num_s[i - j - 1];
num_s[i - j - 1] = temp;
}
num = atoi(num_s);
puts("Enter words to add to the file; press the #");
puts("key at the beginning of a line to terminate.");
while ((fscanf(stdin, "%s", words) == 1) && (words[0] != '#'))
fprintf(fp, "[%d]%s\n", ++num, words);
puts("File contents:");
rewind(fp);
while (fscanf(fp, "%s", words) == 1)
puts(words);
if (fclose(fp) != 0)
fprintf(stderr, "Error closing file.\n");
return 0;
}
大神好
，我想问一下我在每次打开文件时，获取每个单词的序号的代码我是这样写的，结果导致了只 
用第一次运行程序时可以添加单词，后面再运行就添加不了单词，我很苦恼 
，不知道为什么，请大神帮忙看看 
我写入单词时在单词前面加了“[单词对应序号]”
#include
#include
int main()
{
FILE *fp;
char words[50];
int count, ch; //编号
if((fp = fopen("a.txt", "ab+")) == NULL)
{
fprintf(stderr, "Open of %s is fail!", "a.txt");
exit(1);
}
rewind(fp);
//找到上次最后一个编号
while( (ch = getc(fp)) != '[' && ch != EOF)
continue;
if(ch == EOF)
count = 0;
else
{
ch = getc(fp);
count = atoi(ch);
}
//添加单词到文件中
puts("Enter words to add to the file; press #");
puts("to quit.");
while( (fscanf(stdin, "%s", words) == 1) && (words[0] != '#') )
{
printf("%d***", count);
fprintf(fp, "[%d]%s ", ++count, words); //将读取的单词输出到文件
}
puts("File contents:");
rewind(fp); //回到文件开始
//显示文件内容
while(fscanf(fp, "%s", words) == 1)
puts(words);
puts("done!");
if(fclose(fp) != 0)
{
fprintf(stderr, "Error in closing file!");
exit(1);
}
return 0;
}