我原本就有寫一個程式是做資料分析的
現在遇到一個問題
如果我只要這份資料的抓前30個字元資料出來該如何寫呢

例 test.txt 資料很多
內容 id55203060,0,1,2,3,4,5,6,4,7,3,2,3,6,4,5
id55203061,0,1,2,3,4,5,6,4,7,3,3,5,6,4,8
id55203062,0,1,2,3,4,5,6,4,7,3,3,6,9,8,5
..........


id55203060,0,1,2,3,4,5,6,4,7,3
id55203061,0,1,2,3,4,5,6,4,7,3
id55203062,0,1,2,3,4,5,6,4,7,3
........
........

我只需要前面30個字元該如何寫呢

char dest[31];

memset(dest, '\0', 31);

memcpy(dest, src, 30);

//Try it!

------
What do we live for if not to make life less difficult for each other?

出不來，請看看~~~
[code cpp]
#include
#include
void main()
{
char dest[50];
FILE *stream = fopen("kindout.dat","r");
fscanf(stream, " %s", &dest);
memset(dest, '\0', 50);
memcpy(dest, 'scr, 30);
fclose(stream);
}

[/code]

#include <string.h>
#include
void main()
{
char dest[60];
FILE *stream;
stream=fopen("kindout.dat","r");
while (!feof(stream))
{
memset(dest,'\0',60);
fscanf(stream, "%s", &dest);
memset(&dest[30],'\0',30);
printf("%s\n", dest);
}
fclose(stream);

}

------
What do we live for if not to make life less difficult for each other?