fprintf 打印乱码

Question

I have the following block of code:

while(true){
      if(feof(stdin)!=0){
        break;
      }
      fgets(fileText2,1000,stdin);
      //flag E
      if(strchr(flags,'A')||strchr(flags,'E')){
        if(fileText2!=NULL&&strlen(fileText2)>0){
          fileText2[strlen(fileText2)-1]='$';
          fileText2[strlen(fileText2)]='\n';
          fileText2[strlen(fileText2)+1]='\0';
        }
      }
      
      fprintf(stdout,"%s",fileText2);
      memset(fileText2,0,1000);
    }

I am redirecting the contents of a file to the standard input using the < operator.

The file looks like:

omcunneecnucnwencnwecwe
cwec
c
wc
wec
wc
wec
wec
ecwccwc
wec
wecw we
ew
 e
 wecwe
c we e ewwe   ewwe
w
 we
wec
ec


ceec

and is a unix line termination file. The first line it prints the omcunneecnucnwencnwecwe , but before printing the second sentence ( cwec ), it prints some garbage characters. This only happens after the first line, and all others are fine.

The following is an example of the output:

omcunneecnucnwencnwecwe$
h_cwec$
c$
wc$
wec$
wc$
wec$
wec$
ecwccwc  $
wec$
wecw we $
ew$
 e$
 wecwe$
c we e ewwe   ewwe $
w$
 we$
wec$
ec$
$
$
ceec$

How do I get rid of those garbage characters? (The dollar characters are not garbage, only the second line ones before the actual sentence in the file)

EDIT: fileText2 is defined as char fileText2[1000];

Answer 1

This overwrites the trailing null character .

fileText2[strlen(fileText2)]='\n';

Now strlen(fileText2) below is bad as fileText2 is no longer certainly null character terminated - not a string .

fileText2[strlen(fileText2)+1]='\0';  // UB

---

When fgets() return NULL (when end-of-file occurs),

fgets(fileText2,1000,stdin);

Then the following strlen(fileText2) reflects the previous line.

Instead:

//while(true){
//  if(feof(stdin)!=0){
//    break;
//  }
//  fgets(fileText2,1000,stdin);
while (fgets(fileText2, sizeof fileText2, stdin)) {
  ...