在我的程序中，我试图打开命令行提供的文本文件，然后创建两个新的文本文件 values1.txt 和 values2.txt。命令行提供的文件包含100个唯一的整数。一半的数字被复制到values1.txt中，另一半被复制到values2.txt中。
然而，当我试图对values1.txt进行操作时，我得到了下面的值。
101
32758
0
0
176197744
32764
3
0
176197728
32764
0
0
-78325960
32758
0
0
1
0
-78326000
32758
0
0
1700966438
0
-78325096
32758
176197896
32764
176197952
32764
-78326000
32758
0
0
-80547345
32758
0
0
176197952
32764
0
0
0
0
0
0
-78326000
32758
-82942073
32758
8
这是我的代码
#include<stdio.h>
#include<stdlib.h>
#include <string.h>
int cfileexists(const char * filename){
/* try to open file to read */
FILE *file;
if (file = fopen(filename, "r")){
fclose(file);
return 1;
}
}
int main(int argc,char*argv[]){
char *p= argv[1];
int numArray[100];
int i=0;
int sum1arr[50];
int sum2arr[50];
if (! cfileexists(p)){
printf("Error, unable to locate the data file %s\n", p);
return 100;
}
for(i;i<100;i++){
FILE *stream=fopen(p,"r");
while(!feof(stream)){
fscanf(stream,"%d",&numArray[i]);
}
FILE * fPtr = NULL;
fPtr = fopen("values1.txt", "w");
for(int j=0;j<50;j++){
fprintf(fPtr,"%d\n",numArray[j]);
}
}
}
为了便于比较，这是源文本文件。
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
脚本中，我想打开命令行提供的文本文件，然后创建两个新的文本文件values1.txt和values2.txt。for 语句有太多的循环，你应该使用读循环也写，你也可以使用fscanf return来验证文件何时到达终点。如果你不需要保存值，你甚至可以使用singe int 来暂时存储该值，直到它被写入。
这里是一个可能的实现，并附有注释。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int cfileexists(const char *filename)
{
/* try to open file to read */
FILE *file;
if ((file = fopen(filename, "r")))
{
fclose(file);
return 1;
}
return 0; //return 0 if file not found
}
int main(int argc, char *argv[])
{
if(argc != 2){ //check number of arguments
puts("Wrong number of arguments");
return(EXIT_FAILURE); //EXIT_FAILURE macro is more portable
}
FILE *stream;
FILE *fPtr = NULL;
FILE *fPtr2 = NULL;
int numArray[100];
int i = 0;
fPtr = fopen("values1.txt", "w");
fPtr2 = fopen("values2.txt", "w");
//you can use fopen to check file nstead of the
//function, it returns null if no file is opened
if (!(stream = fopen(argv[1], "r")))
{
perror("Error, unable to locate the data file"); //also prints error signature
return EXIT_FAILURE;
}
//check input, stop when there is nothing else to read
while (fscanf(stream, "%d", &numArray[i]) == 1 && i < 100)
{
if(i < 50)
fprintf(fPtr, "%d\n", numArray[i]); //write to file 1
else
fprintf(fPtr2, "%d\n", numArray[i]); //write to file 2
i++;
}
fclose(stream);
fclose(fPtr);
fclose(fPtr2);
}
这里有一个不同的方法，使用 getline():
#include <stdio.h>
#include <stdlib.h>
#define SPLIT_POINT 50
int main(void) {
char filename[] = "test";
FILE *fp = fopen(filename, "r");
if (!fp) {
fprintf(stderr, "Couldn't open %s\n", filename);
}
// Check file open (as above) left out for brevity
FILE *out1 = fopen("values1.txt", "w");
FILE *out2 = fopen("values2.txt", "w");
char *line = NULL;
size_t n = 0, i = 0;
ssize_t len = 0;
while ((len = getline(&line, &n, fp)) != EOF) {
// Select which output file to write to
FILE *out = i < SPLIT_POINT ? out1 : out2;
// getline includes the newline - remove this
if (i == SPLIT_POINT - 1 && len > 0) {
line[--len] = 0;
}
// Write to the relevant output file
fprintf(out, "%s", line);
i++;
}
fclose(fp);
fclose(out1);
fclose(out2);
free(line);
return 0;
}
如果你不在乎删除新行，你可以简化以下内容 getline() 呼叫--只是不要打扰 len 可变的。