字符串操作程序不返回预期输出 [英] String manipulation program not returning expected output

问题描述

嗨。我写了一个小程序来学习用C语写。但不幸的是输出都混乱了并且不好看。

/ * read_file.c

整个此代码的一点是从文件中读取整个内容，然后将数据排列为单个字符串。 * /


#include< stdio.h>


char * returnArrayFromFile（char * file_name）{

//尝试打开文件

FILE * text_file = fopen（file_name，" r"）;


//文件中的字符总数。

int m = 0;

while（feof（text_file）== 0）{

fgetc（text_file）; m ++;

}

fclose（text_file）;

fopen（" text_file"，" r"）;


char file_content [m];


int i = 0;

while（i< m）{

fscanf（text_file，"％c"，& file_content [i ++]）;

}


fclose（text_file）;


返回file_content;

}

/ * substring.c

从ABC * /
char * getSubstring（char * larger，int a，int b）{

char * smaller =（char *）malloc（sizeof（char）* b）;

int i;

for（i = 0; i< b; i ++）{

if（large [a + i] ==''\\ \\ 0''）{

休息;

}

较小[i] =较大[a + i];

}

返回较小;

}


/ * main.c * /

#include" read_file.h"

#include" substring.h"

int main（int argc，char * argv []）{

char * file_name = argv [1];

int a = atoi（a rgv [2]）;

int b = atoi（argv [3]）;

char * larger = returnArrayFromFile（file_name）;

char * small = getSubstring（更大，a，b）;

printf（"％s"，更小）;

}


/ *最后，text_file * /

abcdefghi


如果我用gcc * .c -o main编译它们并执行


main text_file 3 3


我期待输出


def


但是我得到了其他人混乱的人物。

解决方案

Logan Lee< Lo ******* **@student.uts.edu.auwrites：

嗨。我已经写了一个小程序来学习用C语写。但不幸的是输出都是混乱而且不好。


/ * read_file.c

此代码的重点是从文件中读取整个内容，然后将数据排列为单个字符串。 * /


#include< stdio.h>


char * returnArrayFromFile（char * file_name）{

//尝试打开文件

FILE * text_file = fopen（file_name，" r"）;


//文件中的字符总数。

int m = 0;

while（feof（text_file）== 0）{

fgetc（text_file）; m ++;

}

fclose（text_file）;

fopen（" text_file"，" r"）;


char file_content [m];


int i = 0;

while（i< m）{

fscanf（text_file，"％c"，& file_content [i ++]）;

}


fclose（text_file）;


返回file_content;

}


/ * substring.c

从ABC返回B * /

char * getSubstring（char * larger，int a，int b）{

char * smaller =（char *）malloc（sizeof（char）* b） ;

int i;

for（i = 0; i< b; i ++）{

if（large [a + i] = =''\'''）{

休息;

}

较小[i] =较大[a + i]; < br $>
}

返回较小;

}


/ * main.c * /

#include" read_file.h"

#include" substring.h"

int main（int argc，char * argv []）{

char * file_name = argv [1];

int a = atoi（argv [2]）;

int b = atoi（argv [3]）;

char * larger = returnArrayFromFile（file_name）;

char * smaller = getSubstring（large，a，b）;

printf（"％s"，small ）;

}


/ *最后，text_file * /

abcdefghi


如果我用gcc * .c -o main编译它们并执行


main text_file 3 3


我在期待输出


def


但是我的其他人都是乱七八糟的人物。

我忘了包含头文件，但从给出的代码中可以看出它们很明显。

> int m = 0;

while（feof（text_file）== 0）{

fgetc（text_file）; m ++;

}

fclose（text_file）;

fopen（" text_file"，" r"）;

- >>>>>> char file_content [m];


你使用哪种编译器？

突出显示的行让我产生怀疑。你可以这样做吗？

12月15日下午1:40，krishan< srikrishanma ... @ gmail.comwrote：
< blockquote class =post_quotes>

int m = 0;

while（feof（text_file）== 0）{

fgetc（text_file）; m ++;

}

fclose（text_file）;

fopen（" text_file"，" r"）;

- >>>>>> char file_content [m];


你使用哪种编译器？

突出显示的行让我产生怀疑。你能这样做吗？

WOW gcc允许我这样做.....

Hi. I''ve written a small program to learn to write in C. But unfortunately the output is all jumbled up and not nice.
/* read_file.c
The whole point of this code is to read the entire content from a file then arrange the data as a single string. */

#include <stdio.h>

char* returnArrayFromFile(char* file_name) {
// Try opening a file
FILE *text_file=fopen(file_name,"r");

// Total number of characters in the file.
int m=0;
while(feof(text_file)==0) {
fgetc(text_file); m++;
}
fclose(text_file);
fopen("text_file","r");

char file_content[m];

int i=0;
while(i<m) {
fscanf(text_file, "%c", &file_content[i++]);
}

fclose(text_file);

return file_content;
}
/* substring.c
Return B from ABC */
char* getSubstring(char* larger, int a, int b) {
char* smaller=(char *)malloc(sizeof(char) * b);
int i;
for(i=0; i<b; i++) {
if (larger[a+i]==''\0'') {
break;
}
smaller[i]=larger[a+i];
}
return smaller;
}

/* main.c */
#include "read_file.h"
#include "substring.h"

int main(int argc, char* argv[]) {
char* file_name=argv[1];
int a=atoi(argv[2]);
int b=atoi(argv[3]);
char* larger=returnArrayFromFile(file_name);
char* smaller=getSubstring(larger, a, b);
printf("%s", smaller);
}

/* Lastly, text_file */
abcdefghi

If I compile them with gcc *.c -o main and execute by

main text_file 3 3

I''m expecting the output

def

But I''m getting others with jumbled characters.

解决方案

Logan Lee <Lo*********@student.uts.edu.auwrites:

Hi. I''ve written a small program to learn to write in C. But unfortunately the output is all jumbled up and not nice.
/* read_file.c
The whole point of this code is to read the entire content from a file then arrange the data as a single string. */

#include <stdio.h>

char* returnArrayFromFile(char* file_name) {
// Try opening a file
FILE *text_file=fopen(file_name,"r");

// Total number of characters in the file.
int m=0;
while(feof(text_file)==0) {
fgetc(text_file); m++;
}
fclose(text_file);
fopen("text_file","r");

char file_content[m];

int i=0;
while(i<m) {
fscanf(text_file, "%c", &file_content[i++]);
}

fclose(text_file);

return file_content;
}
/* substring.c
Return B from ABC */
char* getSubstring(char* larger, int a, int b) {
char* smaller=(char *)malloc(sizeof(char) * b);
int i;
for(i=0; i<b; i++) {
if (larger[a+i]==''\0'') {
break;
}
smaller[i]=larger[a+i];
}
return smaller;
}

/* main.c */
#include "read_file.h"
#include "substring.h"

int main(int argc, char* argv[]) {
char* file_name=argv[1];
int a=atoi(argv[2]);
int b=atoi(argv[3]);
char* larger=returnArrayFromFile(file_name);
char* smaller=getSubstring(larger, a, b);
printf("%s", smaller);
}

/* Lastly, text_file */
abcdefghi

If I compile them with gcc *.c -o main and execute by

main text_file 3 3

I''m expecting the output

def

But I''m getting others with jumbled characters.

I forgot to include header files but they are obvious from the code given.

>int m=0;

while(feof(text_file)==0) {
fgetc(text_file); m++;
}
fclose(text_file);
fopen("text_file","r");

-->>>>>> char file_content[m];

Which compiler are u using?
The highlighted line makes me suspicious. can u do that ?

On Dec 15, 1:40 pm, krishan <[e-mail]:

int m=0;
while(feof(text_file)==0) {
fgetc(text_file); m++;
}
fclose(text_file);
fopen("text_file","r");

-->>>>>> char file_content[m];

Which compiler are u using?
The highlighted line makes me suspicious. can u do that ?

WOW gcc allows me to do that.....

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