文件操作代码练习

main.cpp

// oj_file_operation.cpp : Defines the entry point for the console application.

//

#include "stdafx.h"

extern int number_operate(char *inFile, char *outFile);

int main(int argc, char* argv[])

{

printf("Hello World!\n");

// number_operate("e:\tmp\in_data.txt", "e:\tmp\out_data.txt");

number_operate("e://tmp/in_data.txt", "e://tmp/out_data.txt");

return 0;

}

file_read_write.cpp

#include "stdafx.h"

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

char *get_digit_start(char *p_in)

{

char *p_start = p_in;

int i = 0;

//while 循环写法

//入参检查

for (i = 0; i < strlen(p_in); i++) //"\n"

{

if (p_in[i] == ' ')

{

p_start++;

continue;

}

if (p_in[i] < '0' || p_in[i] > '9')

{

return NULL;

}

if (p_in[i] >= '0' && p_in[i] <= '9')

{

break;

}

}

return p_start;

}

char *get_digit_end(char *p_in)

{

char *p_end = p_in;

int len = 0;

int i = 0;

len = strlen(p_in);

p_end = &p_in[len - 2]; //"\n"

//相等条件

while (p_end != p_in)

{

if (*p_end < '0' || *p_end > '9')

{

return NULL;

}

if (*p_end == ' ')

{

p_end--;

continue;

}

if (*p_end >= '0' && *p_end <= '9')

{

break;

}

}

return p_end;

}

/*

int is_digit_chars(char *pin)

{

}

*/

int number_operate(char *inFile, char *outFile)

{

FILE *fp = NULL;

FILE *fp_out = NULL;

char line_chars[65];

char out_chars[65];

char *p_digit_start = NULL;

char *p_digit_end = NULL;

char *p_tmp = NULL;

int i = 0;

int is_digit_chars = 1;

if (NULL == (fp = fopen(inFile, "r+")))

{

printf(" inFile file opened error");

perror("perror");

return -1;

}

if (NULL == (fp_out = fopen(outFile, "w+")))

{

printf("outFile file opened error");

perror("perror");

return -1;

}

while (! feof(fp))

{

fgets(line_chars, sizeof(line_chars), fp); //末尾有换行符 \n

printf("%s\n", line_chars);

p_digit_start = line_chars;

if(NULL == ((p_digit_start = get_digit_start(line_chars))))

{

continue;

}

if(NULL == ((p_digit_end = get_digit_end(line_chars))))

{

continue;

}

p_tmp = p_digit_start;

while (p_tmp != p_digit_end)

{

if (*p_tmp < '0' || *p_tmp > '9')

{

is_digit_chars = 0;

break;

}

p_tmp++;

}

if (1 != is_digit_chars)

{

is_digit_chars = 1;

continue;

}

//should add /n

strncpy(out_chars, p_digit_start, p_digit_end - p_digit_start + 1);

out_chars[p_digit_end - p_digit_start + 1] = '\0';

//out_chars[p_digit_end - p_digit_start + 2] = '\r';

//out_chars[p_digit_end - p_digit_start + 3] = '\n';

printf("out file %s \n", out_chars);

fputs(out_chars, fp_out);

fputs("\n", fp_out); //换行

}

return 1;

}