Question

#include <stdio.h>
#include <stdlib.h>
int main ( int argc, char *argv[] )
{
//sets the number of lines ot be read  
char strline[10000]; 
// checks to see that there are only 2 entries in the argv by checking in argc
if ( argc != 2 )
    {
        printf( "ERROR. Enter a file name\n", argv[0] );
    }
    else 
    {
       //opens the file which was entered by the user as read only 
       FILE *infile = fopen( argv[1], "r");
        // covers a miss spelling of a file name or file doesn't exist
        if ( infile == 0 )
        {
            printf( "ERROR. Did you make a mistake in the spelling of the file or the File entered doesn't exist\n" );
        }
        else 
        {
            // File exists read lines, while not at the end of the file
while  (!feof(infile))
                {   
//Get next line to be printed up to 126 characters per a line
if(fgets(strline, 126, infile))
            {
                //print the current line (stored in strline)
printf("%s",strline);
            }
        }
    //closes the file
fclose( infile );
    return 0;        
    }
    }
}

在第6行（上面的评论）我已经声明这是程序可以读取的最大行数。昨天我被告知事实并非如此。

有人可以向我解释代码行的实际含义吗？

char strline[10000];

所以从人们所说的是什么设置为128更多的东西（126为fgets和一些房间）

Answer 1

char strline [10000];您已经分配了一个10,000字节长的缓冲区：

           +--------------...-+
strline -> |      10000       |
           +--------------...-+

如果你想分配10,000行而你需要这样的东西：

char* strline[10000]; // array of 10,000 pointers to strings

访问行将分配给数组中的每个条目

strline[0]
strline[1]
...
strline[10000]

比如读取一行时你需要为该行分配一个缓冲区，然后从strline指向它

char* line = malloc( linelength + 1 );
fgets( line, linelength, fp );
strline[0] = line;

              +-------+
strline[0] -> | line  |
              +-------+

C读取文件行最大计数

1 个答案: