C语言如何读取txt文本里面的内容？

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C语言如何读取txt文本里面的内容？,第1张

C语言可以使用fopen（）函数读取txt文本里。

示例：

#include <stdio.h>

FILE *stream, *stream2

void main( void )

{

int numclosed

/* Open for read (will fail if file "data" does not exist) */

if( (stream  = fopen( "data", "r" )) == NULL )

printf( "The file 'data' was not opened\n" )

else

printf( "The file 'data' was opened\n" )

/* Open for write */

if( (stream2 = fopen( "data2", "w+" )) == NULL )

printf( "The file 'data2' was not opened\n" )

else

printf( "The file 'data2' was opened\n" )

/* Close stream */

if(fclose( stream2 ))

printf( "The file 'data2' was not closed\n" )

/* All other files are closed: */

numclosed = _fcloseall( )

printf( "Number of files closed by _fcloseall: %u\n", numclosed )

}

扩展资料

使用fgetc函数

#include <stdio.h>

#include <stdlib.h>

void main( void )

{

FILE *stream

char buffer[81]

int  i, ch

/* Open file to read line from: */

if( (stream = fopen( "fgetc.c", "r" )) == NULL )

exit( 0 )

/* Read in first 80 characters and place them in "buffer": */

ch = fgetc( stream )

for( i=0(i <80 ) &&( feof( stream ) == 0 )i++ )

{

buffer[i] = (char)ch

ch = fgetc( stream )

}

/* Add null to end string */

buffer[i] = '\0'

printf( "%s\n", buffer )

fclose( stream )

}

//data.txt文件内容如下\x0d\x0a\x0d\x0a1个猪\x0d\x0a2个猪\x0d\x0a3个猪\x0d\x0a4个猪\x0d\x0a5个猪\x0d\x0a6个猪\x0d\x0a7个猪\x0d\x0a8个猪\x0d\x0a\x0d\x0a//运行结果一\x0d\x0athe 8 line :8 个 猪\x0d\x0a\x0d\x0aPress any key to continue \x0d\x0a//运行结果二\x0d\x0aout of range!\x0d\x0aPress any key to continue \x0d\x0a\x0d\x0a//代码如下\x0d\x0a#include \x0d\x0a#include \x0d\x0a#include \x0d\x0amain(void)\x0d\x0a{\x0d\x0aint lid,cnt=0,flag=0\x0d\x0achar buf[100]="\0"\x0d\x0aFILE *fp\x0d\x0a\x0d\x0asrand((unsigned)time(NULL))\x0d\x0afp=fopen("data.txt","r")\x0d\x0alid= rand()%10+1\x0d\x0awhile (fgets(buf,99,fp)!=NULL)\x0d\x0a{\x0d\x0aif(cnt==lid)\x0d\x0a{\x0d\x0aprintf("the %d line :%s\n",lid+1,buf)\x0d\x0aflag=1\x0d\x0abreak\x0d\x0a}\x0d\x0acnt++\x0d\x0a}\x0d\x0aif (flag==0)\x0d\x0a{\x0d\x0aprintf("out of range!\n")\x0d\x0a}\x0d\x0a}

1 以fopen打开文件，使用"r"方式。

2 通过fscanf，按照文件中的数据格式，读入数据。

3 关闭文件并使用数据。

如文件in.txt中存在三个以空格分隔的数据，依次为整型，字符串，以及浮点型，则读取数据的代码可以写作：

int main()

{

    FILE *fp

    int a

    char s[100]

    float f

    fp = fopen("in.txt", "r")

    if(fp == NULL) return -1//打开文件失败，结束程序。

    fscanf(fp,"%d%s%f",&a,s,&f)

    fclose(fp)

    

    printf("read value: %d, %s, %f", a,s,f)

}