strings...

I'm working on a small little project to simulate the linux OS for complete newbies and I was wondering, I kept trying to find a way to use ifs and else statements for them to analyze the char variable and do something. But I can never get it to read the char variables in any of the if's statements. I've researched the net a bit, and have not been successfull. A snippet of the code is:

printf("\n > ");
gets(temp);
if (temp=='ls')
{
printf("testing");
}

else { printf("Something went wrong....beta code"); }



btw, yes i declared all vars, and i did everything needed, i'm not THAT stupid ;P. So if someone could please hook me up, i'd be very thankful. :)


p.s. if your a C string god, is there anyway to add an effect to the printed characters to make then like seem to type by themselves on letter at a time? If not, thanx anway. =)

i think (temp=='ls) should be (temp=="ls")
or try if (strcmp(temp,"ls")) ....

Quote:

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small little project to simulate the linux OS for complete newbies

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small? :D

Uh... You don't say how you declared "temp" well, if you declared it like so:

char temp;

then temp can only hold 1 (one) character therefore the statement

if(temp == 'ls')

will always return false due to limited range of data type (char) such that "something will always go wrong...beta code". However if you defined temp as

char *temp;

Then, I think you would like to use the following statement

if(temp == "ls") /* note the double quotes */

If you defined temp as

char temp[SIZE];

Then, you should use:

if((strcmp(temp, "ls")) == 0)

this also works for the latter case.
about characters typing themselves one letter at a time. You probably should use an array e.g

char temp[10];
int i;

for(i = 0;i <= 10;i++) {
putc(temp[i], stdout);
/*delay for a considerable amount of time e.g*/
usleep(100); /* delays for 100 microseconds */
}

or if you use

char *temp;

try:

while(*temp != '\0') {
putc(*temp, stdout);
temp++;
/*delay for a considerable amount of time e.g*/
usleep(100); /* delays for 100 microseconds */
}



etc....

have fun,

Is usleep ANSI?

I did a quick man and the documentation is written by Redhat people which suggests to me that it may be specific to Linux or even just Redhat. :(

I guess it wouldn't matter if you were running it on Linux but I would have thought that one wouldn't write a Linux simulator to run on Linux.

Alternately you could write a loop that does nothing but look at the time between key outputs.

eg.

Code:

---

for(i=0;i<(sizeof(string[])/sizeof(char));i++)
{
  putchar((int)string[i]);
  starttime=time();
  /* loop for some time */
  while(wasted!=WAITTIME)
  {
    wasted=difftime(starttime,time());
  }
}

---

Code:

---

char temp[100];
gets(temp);
if ( strcmp(temp,"ls") == 0 )
{
  printf("testing");
}

---

Later on, you will need to use fgets instead of gets - because gets is a big bug trap

Quote:

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Originally posted by limerick
Is usleep ANSI?

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usleep() is not ANSI (and was not written by Red Hat). It conforms to BSD 4.3.