How to exit program???

**spottedzebra** · 06-20-2010

I am working my way through "The C Programming Language".

I am on the topic of input/output in the first chapter and at the end of the section we are supposed to write a program that counts the spaces, tabs, and new lines. I wrote the program no problem but i can't get the program to exit and give me the output for number of spaces, tabs, and new lines.

i even tried on of the simpler programs from the book just to make sure it wasn't my logic. it wasn't, i just don't know how to exit the program correctly.

here is what i have for reference (my program):

Code:

#include <stdio.h>

main()
	{
	int c;	/* Counting variable */
	int ns = 0;	/* Number of spaces */
	int nl = 0; /* Number of lines */
	int nt = 0;	/* Number of tabs */
	
	for ( c = 0; (c = getchar()) != EOF; c++)
		{
		if( c == '\t')
			{
			nt++;
			}
		if( c == '\n')
			{
			nl++;
			}
		if( c == ' ')
			{
			ns++;
			}		
		}
	printf("%d\t%d\t%d\n", ns, nt, nl);	
	}

thanks in advance.

**nullifyed** · 06-20-2010

exit(0); ->SUCCESS_EXIT
exit(1); ->FAILURE_EXIT

also there is another option brake; which does not exit a program but brakes a loop (just in case)!

**jimtuv** · 06-20-2010

you should use

Code:

int main (void)

and at the bottom

Code:

return 0;

**KBriggs** · 06-20-2010

for ( c = 0; (c = getchar()) != EOF; c++)

Why are you incrementing c? If you are getting something from the input stream each time, the c++ deosn't actually have any effect.

**laserlight** · 06-20-2010

Originally Posted by spottedzebra

I wrote the program no problem but i can't get the program to exit and give me the output for number of spaces, tabs, and new lines.

What exactly do you mean by "can't get the program to exit"? Perhaps you find that the command prompt window flashes by too quickly for you to view the output? If so, just run the program from the command prompt, or use getchar() to wait for input so that the window stays open.

Originally Posted by =nullifyed

exit(0); ->SUCCESS_EXIT
exit(1); ->FAILURE_EXIT

The macros are EXIT_SUCCESS and EXIT_FAILURE. They are implementation defined.

Originally Posted by nullifyed

also there is another option brake; which does not exit a program but brakes a loop (just in case)!

Actually, the keyword is break, though now I am tempted to be funny and #define brake break

**nullifyed** · 06-20-2010

Originally Posted by laserlight

What exactly do you mean by "can't get the program to exit"? Perhaps you find that the command prompt window flashes by too quickly for you to view the output? If so, just run the program from the command prompt, or use getchar() to wait for input so that the window stays open.

The macros are EXIT_SUCCESS and EXIT_FAILURE. They are implementation defined.

Actually, the keyword is break, though now I am tempted to be funny and #define brake break

xaxaxaa

good!!! sorry...i am not good at english and my head is NOT Ok....

**spottedzebra** · 06-20-2010

thanks for all the replies so quickly. i am a noob at C so i don't fully understand all of your responses and it would seem to me i wouldn't need to use anything advanced (i.e. not already taught in the book i am using)

Originally Posted by nullifyed

exit(0); ->SUCCESS_EXIT
exit(1); ->FAILURE_EXIT

also there is another option brake; which does not exit a program but brakes a loop (just in case)!

i am not sure what this is/means. i have not been introduced to anything like this yet.

Originally Posted by jimtuv

you should use

Code:

int main (void)

and at the bottom

Code:

return 0;

same goes for this.

Originally Posted by KBriggs

Why are you incrementing c? If you are getting something from the input stream each time, the c++ deosn't actually have any effect.

me being a noob. thanks for the catch, i took it out.

Originally Posted by laserlight

What exactly do you mean by "can't get the program to exit"? Perhaps you find that the command prompt window flashes by too quickly for you to view the output? If so, just run the program from the command prompt, or use getchar() to wait for input so that the window stays open.

The macros are EXIT_SUCCESS and EXIT_FAILURE. They are implementation defined.

Actually, the keyword is break, though now I am tempted to be funny and #define brake break

i executing the program directly in the command prompt so I am not missing it popping up.

what i mean by not being able to exit the program is this.

I load the program (running ubuntu and using the preload compiler) :

Code:

./a.out

then i allows me to input whatever combination of characters i want.

now i want it to count the spaces, tabs, and lines but i don't know how to make it finish or exit, meaning it prints the output in the command prompt.

if the printf command is moved inside the 'for' loop it will work but it will have output every time i press enter. the counting will be correct but this is not what the program is supposed to do.

here is a basic program from the text for reference to what i am learning from: ( i did not write this one )

Code:

#include <stdio.h>
/* count lines in input */
main()
{
int c, nl;
nl = 0;
while ((c = getchar()) != EOF)
if (c == '\n')
++nl;
printf("%d\n", nl);
}

thanks again to everyone for the help

**Bayint Naung** · 06-20-2010

For EOF, hit ctrl+d.

**nullifyed** · 06-20-2010

Originally Posted by Bayint Naung

For EOF, hit ctrl+d.

exactly. just type space tab enter many times and then crt&D....

**jimtuv** · 06-20-2010

This may explain why you should be using

Code:

int main (void){

      //your program goes here

       return 0;
}

Cprogramming.com FAQ > main() / void main() / int main() / int main(void) / int main(int argc, char *argv[])

I hope it helps you understand a bit more. This is not advanced it's just standard with C99.

**spottedzebra** · 06-21-2010

Originally Posted by Bayint Naung

For EOF, hit ctrl+d.

thats exactly what i needed. my program works perfectly not that it is anything special.

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