[英]create array of pointers to files in C programming
#include <stdio.h>
int main(int argc, char *argv[])
{
FILE *fp[argc-1];
int numofProc=argc;
unsigned addr;
char rw;
unsigned int divNum=4096;
int i;
for(i=1;i<=argc;i++){
fp[i-1]=fopen(argv[i],"r");
}
for(i=0;i<argc;i++){
while(fscanf(fp[i],"%x %c", &addr, &rw)==2){
printf("addr : %x \n", addr/divNum);
}
}
for(i=0;i<argc;i++){
fclose(fp[i]);
}
return 0;
}
I want to open some text files in C programming.我想在 C 编程中打开一些文本文件。 I made my code like this.
我像这样制作了我的代码。 When I push 2 text files in my code, It prints all of first text file and prints all of second text file.
当我在代码中推送 2 个文本文件时,它会打印所有第一个文本文件并打印所有第二个文本文件。 But, at last It returns segmentation fault.... I don't know which part is wrong.
但是,最后它返回分段错误......我不知道哪个部分是错误的。 Why this code return segmentation fault at last?
为什么这段代码最后返回分段错误?
You have off-by-one error.你有一对一的错误。 Typically the first argument is the file name of the executable, and second and later arguments are provided parameters.
通常,第一个参数是可执行文件的文件名,第二个和后面的参数是提供的参数。
Therefore, the will be argc - 1
file names, not argc
.因此,将是
argc - 1
文件名,而不是argc
。 Using NULL
as file parameter (returned from failed fopen()
) of fscanf()
may cause Segmentaiton Fault.使用
NULL
作为fscanf()
文件参数(从失败的fopen()
返回fscanf()
可能会导致分段错误。
Fix the number of files to deal with.修复要处理的文件数量。 You declared
numofProc
, so it seems you should use that.您声明了
numofProc
,因此您似乎应该使用它。
Also you should check if file openings are successful.您还应该检查文件打开是否成功。
Try this:尝试这个:
#include <stdio.h>
int main(int argc, char *argv[])
{
int numofProc=argc-1;
FILE *fp[numofProc];
unsigned addr;
char rw;
unsigned int divNum=4096;
int i;
for(i=0;i<numofProc;i++){
fp[i]=fopen(argv[i+1],"r");
if(fp[i]==NULL){
fprintf(stderr,"failed to open %s\n", argv[i+1]);
for(i--;i>=0;i--){
fclose(fp[i]);
}
return 1;
}
}
for(i=0;i<numofProc;i++){
while(fscanf(fp[i],"%x %c", &addr, &rw)==2){
printf("addr : %x \n", addr/divNum);
}
}
for(i=0;i<numofProc;i++){
fclose(fp[i]);
}
return 0;
}
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