C Primer Plus 第六版 第13章 编程答案

1.

#include <stdio.h> #include <stdlib.h> #include <string.h> #define SIZE 100 int main(void) { int ch;     FILE *fp; int count = 0; char * find; char file[SIZE]; puts("请输入文件名: "); fgets(file, SIZE, stdin); if (find = strchr(file, 'n')) *find = ''; if ((fp = fopen(file, "r")) == NULL) { puts("打开失败"); exit(EXIT_FAILURE); } while ((ch = getc(fp)) != EOF) { putc(ch, stdout);         count++; } fclose(fp); printf("File %s has %d charactersn", file, count); return 0; } 

2.

#include <stdio.h> #include <string.h> #define SIZE 500 int main(int argc, char *argv []) {     FILE * fp1, * fp2; if (argc < 3) { fprintf(stderr, "参数不全n"); return -1; } if ((fp1 = fopen(argv[1], "rb")) == NULL) { fprintf(stderr, "%s 打开失败n", argv[1]); return -1; } if ((fp2 = fopen(argv[2], "wb")) == NULL) { fprintf(stderr, "%s 打开失败n", argv[2]); fclose(fp1); return -1; } char strbuf[SIZE]; int nread = 0; while (1) { memset(strbuf, 0, sizeof(strbuf)); if ((nread = fread(strbuf, sizeof(char), SIZE, fp1)) == 0) break; printf("%dn", nread); fwrite(strbuf, sizeof(char), nread, fp2); } fclose(fp1); fclose(fp2); puts("文件复制成功"); return 0; } 

3.

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <ctype.h> #define SIZE 100 int main(void) {     FILE * fp; char str[SIZE]; char * find; puts("请输入文件名"); fgets(str, SIZE, stdin); if (find = strchr(str, 'n')) *find = ''; if ((fp = fopen(str, "r")) == NULL) { printf("文件 %s 打开失败n", str); return -1; } long count; /*     int ch;     while ((ch = getc(fp)) != EOF)         count++;      */ fseek(fp, 0L, SEEK_END);     count = ftell(fp); fseek(fp, 0L, SEEK_SET); char * st = (char *)malloc(sizeof(char) * count); int ch; int i = 0; while ((ch = getc(fp)) != EOF) {         ch = toupper(ch);         st[i] = ch;         i++; } fclose(fp); if ((fp = fopen(str, "w")) == NULL) { printf("文件 %s 打开失败n", str); return -1; } for (i = 0; i < count; i++) putc(st[i], fp); fclose(fp); free(st); printf("拷贝成功 %dn", i); return 0; } 

4.

#include <stdio.h> int main(int argc, char **argv) {     FILE * fp; int i; int ch; if (argc < 2) { puts("参数不齐"); return -1; } for (i = 1; i < argc; i++) { if ((fp = fopen(argv[i], "rt")) == NULL) { printf("打开 %s 失败n", argv[i]); return -1; } printf("%s 文件: n", argv[i]); while ((ch = getc(fp)) != EOF) putc(ch, stdout); fclose(fp); } return 0; } 

5.

#include <stdio.h> #include <stdlib.h> #include <string.h> #define BUFSIZE 4096 #define SLEN 81 int main(int argc, char *argv []) {     FILE * fp1, * fp2; if (argc < 3) { puts("参数不全"); return -1; } if ((fp1 = fopen(argv[1], "a+")) == NULL) { fprintf(stderr, "打开文件 %s 失败n", argv[1]); return -1; } if (setvbuf(fp1, NULL, _IOFBF, BUFSIZE) != 0) { puts("申请失败"); return -1; } if ((fp2 = fopen(argv[2], "r")) == NULL) { fprintf(stderr, "打开文件 %s 失败n", argv[2]); return -1; } if (setvbuf(fp2, NULL, _IOFBF, BUFSIZE) != 0) { puts("申请失败"); return -1; }      size_t bytes; char temp[BUFSIZE]; while ((bytes = fread(temp, sizeof(char), BUFSIZE, fp2)) > 0) fwrite(temp, sizeof(char), bytes, fp1); if (ferror(fp1) != 0) fprintf(stderr, "Error in reading file %s.n", argv[1]); if (ferror(fp2) != 0) fprintf(stderr, "Error in writing file %s.n", argv[2]); rewind(fp1); int ch; printf("%s contents: n", argv[1]); while ((ch = getc(fp1)) != EOF) putchar(ch); fclose(fp1); fclose(fp2); puts("附加成功"); return 0; } 

6.

#include <stdio.h> #include <stdlib.h> #include <string.h> #define LEN 40 int main(void) {     FILE * fp1, * fp2; char name1[LEN], name2[LEN]; char *find; int ch; int count = 0; puts("请输入文件名: "); fgets(name1, LEN, stdin); if (find = strchr(name1, 'n')) *find = ''; if ((fp1 = fopen(name1, "r")) == NULL) { fprintf(stderr, "文件 %s 打开失败n", name1); return -1; } strncpy(name2, name1, LEN-5);     name2[LEN - 5] = ''; strcat(name2, ".red"); if ((fp2 = fopen(name2, "w")) == NULL) { fprintf(stderr, "文件 %s 打开失败n", name2); return -1; } while ((ch = getc(fp1)) != EOF) if (count++ % 3 == 0) putc(ch, fp2); if (fclose(fp1) != 0 || fclose(fp2) != 0) fprintf(stderr, "Error in closing filesn"); return 0; } 

7.a

#include <stdio.h> int main(int argc, char *argv []) {     FILE * fp1, * fp2; int ch1, ch2; if (argc != 3) { puts("参数不全"); return -1; } if ((fp1 =fopen(argv[1], "r")) == NULL) { printf("%s 打开失败n", argv[1]); return -1; } if ((fp2 =fopen(argv[2], "r")) == NULL) { fclose(fp1); printf("%s 打开失败n", argv[2]); return -1; }      ch1 = getc(fp1);     ch2 = getc(fp2); while (ch1 != EOF || ch2 != EOF) { while (ch1 != EOF && ch1 != 'n') { putchar(ch1);             ch1 = getc(fp1); } if (ch1 != EOF) { putchar('n');             ch1 = getc(fp1); } while (ch2 != EOF && ch2 != 'n') { putchar(ch2);             ch2 = getc(fp2); } if (ch2 != EOF) { putchar('n');             ch2 = getc(fp2); } } if (fclose(fp1) || fclose(fp2)) printf("关闭文件失败"); return 0; } 

7.b

#include <stdio.h> int main(int argc, char *argv []) {     FILE * fp1, * fp2; int ch1, ch2; if (argc != 3) { puts("参数不全"); return -1; } if ((fp1 =fopen(argv[1], "r")) == NULL) { printf("%s 打开失败n", argv[1]); return -1; } if ((fp2 =fopen(argv[2], "r")) == NULL) { fclose(fp1); printf("%s 打开失败n", argv[2]); return -1; }      ch1 = getc(fp1);     ch2 = getc(fp2); while (ch1 != EOF || ch2 != EOF) { while (ch1 != EOF && ch1 != 'n') { putchar(ch1);             ch1 = getc(fp1); } if (ch1 != EOF) { putchar(' ');             ch1 = getc(fp1); } while (ch2 != EOF && ch2 != 'n') { putchar(ch2);             ch2 = getc(fp2); } if (ch2 != EOF) {             ch2 = getc(fp2); } putchar('n'); } if (fclose(fp1) || fclose(fp2)) printf("关闭文件失败"); return 0; } 

8.

#include <stdio.h> int main(int argc, char *argv []) {     FILE * fp; int count = 0; int ch; int i; if (argc < 2) { puts("参数不全"); return -1; } if (argc == 2) { puts("请输入文本 "); while ((ch = getchar()) != EOF) { if (ch == argv[1][0])                 count++; } printf("%s 在文本出现了 %dn",argv[1], count); return 0; } for (i = 2; i < argc; i++, count = 0) { if ((fp = fopen(argv[i], "r")) == NULL) { printf("%s 打开失败n", argv[i]); return -1; } while ((ch = getc(fp)) != EOF) { if (ch == argv[1][0])                 count++; } printf("%s 在 %s 出现了 %dn",argv[1], argv[i], count); fclose(fp); } return 0; } 

9.

#include <stdio.h> #include <stdlib.h> #include <string.h> #define MAX 41 int main(void) {     FILE * fp; char words[MAX]; int count = 0; if ((fp = fopen("wordy", "a+")) == NULL) { puts("打开失败"); return -1; } while ((fgets(words, MAX, fp)) != NULL)         count++; rewind(fp); puts("请输入 #结束"); while ((fscanf(stdin, "%40s", words) == 1) && (words[0] != '#')) fprintf(fp, "%03d: %sn", ++count, words); rewind(fp); while (fgets(words, MAX, fp) != NULL) fputs(words, stdout); fclose(fp); return 0; } 

10.

#include <stdio.h> #include <string.h> #define LEN 1000 char * s_gets(char *st, int n); int main(void) {     FILE * fp; long i; char file[LEN]; puts("请输入文件: "); s_gets(file, LEN); if ((fp = fopen(file, "r")) == NULL) { puts("打开失败"); return -1; } puts("输入开始处: "); while (scanf("%ld", &i) == 1 && i >= 0) { fseek(fp, i, SEEK_SET); memset(file , 0, sizeof(file)); fgets(file, LEN, fp); fputs(file, stdout); } return 0; } char * s_gets(char *st, int n) { char * ret_val; char * find;      ret_val = fgets(st, n, stdin); if (ret_val) { if (find = strchr(st, 'n')) *find = ''; else while (getchar() != 'n'); } return ret_val; } 

11.

#include <stdio.h> #include <string.h> #define LEN 255 int main(int argc, char **argv) {     FILE * fp; char len[LEN]; if (argc != 3) { puts("参数错误"); return -1; } if ((fp = fopen(argv[2], "r")) == NULL) { puts("打开文件失败"); return -1; } while (fgets(len, LEN, fp) != NULL) if (strstr(len, argv[1])) fputs(len, stdout); fclose(fp); return 0; } 

12.

#include <stdio.h> #include <stdlib.h> #define ROWS 20 #define COLS 30 #define LEVELS 10 const char trans[LEVELS + 1] = " .':~*= %#"; void MakePic(int data[][COLS], char pic[][COLS], int rows); int main(void) { int row, col; int picIn[ROWS][COLS]; char picOut[ROWS][COLS]; char fileName[81];     FILE * infile; printf("Enter name of file: "); scanf("%80s", fileName); if ((infile = fopen(fileName, "r")) == NULL) { fprintf(stderr, "Could not open data file.n"); exit(EXIT_FAILURE); } for (row = 0; row < ROWS; row++) for (col = 0; col < COLS; col++) fscanf(infile, "%d", &picIn[row][col]); MakePic(picIn, picOut, ROWS); for (row = 0; row < ROWS; row++) { for (col = 0; col < COLS; col++) putchar(picOut[row][col]); putchar('n'); } fclose(infile); return 0; } void MakePic(int data[][COLS], char pic[][COLS], int rows) { int row, col; for (row = 0; row < rows; row++) for (col = 0; col < COLS; col++)             pic[row][col] = trans[ data[row][col]]; } 

13.

#include <stdio.h> #include <stdlib.h> #define LEVELS 10 const char trans[LEVELS + 1] = " .':~*= %#"; void MakePic(int rows, int cols, int data[rows][cols], char pic[rows][cols]); int main(void) { int row, col; int rows = 20, cols = 30; int picIn[rows][cols]; char picOut[rows][cols]; char fileName[81];     FILE * infile; printf("Enter name of file: "); scanf("%80s", fileName); if ((infile = fopen(fileName, "r")) == NULL) { fprintf(stderr, "Could not open data file.n"); exit(EXIT_FAILURE); } for (row = 0; row < rows; row++) for (col = 0; col < cols; col++) fscanf(infile, "%d", &picIn[row][col]); MakePic(rows, cols, picIn, picOut); for (row = 0; row < rows; row++) { for (col = 0; col < cols; col++) putchar(picOut[row][col]); putchar('n'); } fclose(infile); return 0; } void MakePic(int rows, int cols, int data[rows][cols], char pic[rows][cols]) { int row, col; for (row = 0; row < rows; row++) for (col = 0; col < cols; col++)             pic[row][col] = trans[ data[row][col]]; } 

14.

#include <stdio.h> #include <stdlib.h> #define ROWS 20 #define COLS 30 #define LEVELS 10 const char trans[LEVELS + 1] = " .':~*= %#"; void MakePic(int data[][COLS], char pic[][COLS], int rows); int shizhen(int (*ar)[COLS], int x, int y); int main(void) { int row, col; int picIn[ROWS][COLS]; char picOut[ROWS][COLS]; char fileName[81];     FILE * infile; printf("Enter name of file: "); scanf("%80s", fileName); if ((infile = fopen(fileName, "r")) == NULL) { fprintf(stderr, "Could not open data file.n"); exit(EXIT_FAILURE); } for (row = 0; row < ROWS; row++) for (col = 0; col < COLS; col++) fscanf(infile, "%d", &picIn[row][col]); for (row = 0; row < ROWS; row++) for (col = 0; col < COLS; col++)             picIn[row][col] = shizhen(picIn, row, col); MakePic(picIn, picOut, ROWS); for (row = 0; row < ROWS; row++) { for (col = 0; col < COLS; col++) { putchar(picOut[row][col]); } putchar('n'); } fclose(infile); return 0; } void MakePic(int data[][COLS], char pic[][COLS], int rows) { int row, col; for (row = 0; row < rows; row++) for (col = 0; col < COLS; col++)             pic[row][col] = trans[ data[row][col]]; } int shizhen(int (*ar)[COLS], int x, int y) { int sum; if (x == 0) //上 { if (y == 0) { if (ar[x][y] - ar[x+1][y] > 1 && ar[x][y] - ar[x][y+1] > 1) {                 sum = (ar[x+1][y] + ar[x][y+1]) / 2.0 + 0.5; return sum; } } if (y == COLS - 1) { if (ar[x][y] - ar[x][y-1] > 1 && ar[x][y] - ar[x+1][y] >1) {                 sum = (ar[x][y-1] + ar[x+1][y]) / 2.0 + 0.5; return sum; } } if (ar[x][y] - ar[x][y-1] > 1 &&             ar[x][y] - ar[x-1][y] > 1 &&             ar[x][y] - ar[x][y+1] > 1) {             sum = (ar[x][y-1] + ar[x-1][y] + ar[x][y+1]) / 3.0 + 0.5; return sum; } } if (x == ROWS - 1) //下 { if (y == 0) { if (ar[x][y] - ar[x-1][y] > 1 && ar[x][y] - ar[x][y+1] > 1) {                 sum = (ar[x-1][y] + ar[x][y+1]) / 2.0 + 0.5; return sum; } } if (y == COLS - 1) { if (ar[x][y] - ar[x][y-1] > 1 && ar[x][y] - ar[x-1][y] > 1) {                 sum = (ar[x][y-1] + ar[x-1][y]) / 2.0 + 0.5; return sum; } } if (ar[x][y] - ar[x][y-1] > 1 &&             ar[x][y] - ar[x-1][y] > 1 &&             ar[x][y] - ar[x][y+1] > 1) {             sum = (ar[x][y-1] + ar[x-1][y] + ar[x][y-1]) / 3.0 + 0.5; return sum; } } if (y == 0) //左 { if (ar[x][y] - ar[x-1][y] > 1 &&             ar[x][y] - ar[x][y+1] > 1 &&             ar[x][y] - ar[x+1][y] > 1) {             sum = (ar[x-1][y] + ar[x][y+1] + ar[x+1][y]) / 3.0 + 0.5; return sum; } } if (y == COLS - 1) //右 { if (ar[x][y] - ar[x-1][y] > 1 &&             ar[x][y] - ar[x][y-1] > 1 &&             ar[x][y] - ar[x+1][y] > 1) {             sum = (ar[x-1][y] + ar[x][y-1] + ar[x+1][y]) / 3.0 + 0.5; return sum; } } // 中间  if (ar[x][y] - ar[x-1][y] > 1 &&         ar[x][y] - ar[x+1][y] > 1 &&         ar[x][y] - ar[x][y-1] > 1 &&         ar[x][y] - ar[x][y+1] > 1) {         sum = (ar[x-1][y] + ar[x+1][y] + ar[x][y-1] + ar[x][y+1]) / 4.0 + 0.5; return sum; } return ar[x][y]; } 

文本

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