我彻底无语了.等下我自己来写个.

#include<stdio.h>
int main()
{
FILE *fpold,*fpnew;
int sum=0;
char c;
fpold=fopen("old.txt","r");
fpnew=fopen("new.txt","w"); sum=0;
while(EOF!=(fscanf(fpold,"%c",&c)))
{
if(c>='0'&&c<='9')
{
sum=sum*10+c-'0';
}
else
{
if(sum)
{
fprintf(fpnew,"%d\n",sum);
sum=0;
}
}
}
if(sum)
{
fprintf(fpnew,"%d",sum);
sum=0;
}
fclose(fpold);
fclose(fpnew);
return 0;
}

呵呵,刚学,还有的地方不熟悉,我今天早上在公司又写了一下,成功了:
[CODE]main()
{
FILE *fpold,*fpnew;
int sum=0,i,k=0;
char str[100];
fpold=fopen("old.txt","r");
fpnew=fopen("new.txt","w+");
for(i=0;i<100;i++)
{
fscanf(fpold,"%c ",&str[i]);
if(str[i]>='0'&&str[i]<='9')
{
sum=sum*10+str[i]-'0';
k++;
}
else
{
if(k>0)fprintf(fpnew,"%d ",sum);
k=0;
sum=0;
}
}

fclose(fpold);
fclose(fpnew);
getch();
}
[/CODE]

谢谢斑竹拉,主要是你的那个if(str[i]>='0'&&str[i]<='9')太好了!哈哈,没想到这个.
另外问下 getc();和fprintf(); 对字符来说是不是效果一样啊?