Exercise 1-8 of the C programming language

Is there any way to write this code without an else if? If so how..and can you explain it line by line please :/ I'm really new to C or programming. #include <stdio.h> /* count blanks, tabs and newlines in input */ main() { int c, bl, t, nl; c = 0; bl = 0; t = 0; nl = 0; while ((c = getchar()) != EOF) if (c == ' ') ++bl; else if (c == '\t') ++t; else if (c == '\n') nl; printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl); }

On 2011-08-13, Joseph Santoyo <josephsantoyo@gmail.com> wrote: > Is there any way to write this code without an else if? Sure! > If so how..and > can you explain it line by line please :/ I'm really new to C or > programming. Welcome! > /* count blanks, tabs and newlines in input */ > main() You should probably spell this int main(void) in modern C. > if (c == ' ') > ++bl; > else if (c == '\t') > ++t; > else if (c == '\n') > nl; (You missed the "++" on the last one; it should be "++nl".) You can write this without else if as follows: > if (c == ' ') > ++bl; > if (c == '\t') > ++t; > if (c == '\n') > ++nl; It's not necessarily any better or more efficient, but it'll work. The way I'd probably do it would be: switch (c) { case ' ': ++bl; break; case '\t': ++t; break; case '\n': ++nl; break; default: break; } 'switch' jumps to a case matching the controlling expression, then executes code until it hits a 'break'. It's often relatively efficient for cases where there are many options; compilers may generate smarter code than for the corresponding sequence of else if ()s. > printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl); .... and return 0; here. > } -s -- Copyright 2011, all wrongs reversed. Peter Seebach / usenet-nospam@seebs.net http://www.seebs.net/log/ <-- lawsuits, religion, and funny pictures http://en.wikipedia.org/wiki/Fair_Game_(Scientology) <-- get educated! I am not speaking for my employer, although they do rent some of my opinions.

On Aug 13, 2:10=A0am, Joseph Santoyo <josephsant...@gmail.com> wrote: > Is there any way to write this code without an else if? If so how..and > can you explain it line by line please :/ I'm really new to C or > programming. > > #include <stdio.h> > > /* count blanks, tabs and newlines in input */ > main() > { > =A0 =A0 =A0 =A0 int c, bl, t, nl; > > =A0 =A0 =A0 =A0 c =3D 0; > =A0 =A0 =A0 =A0 bl =3D 0; > =A0 =A0 =A0 =A0 t =3D 0; > =A0 =A0 =A0 =A0 nl =3D 0; > =A0 =A0 =A0 =A0 while ((c =3D getchar()) !=3D EOF) > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 if (c =3D=3D ' ') > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 ++bl; > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 else if (c =3D=3D '\t') > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 ++t; > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 else if (c =3D=3D '\n') > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 nl; > =A0 =A0 =A0 =A0 printf("There are %d blanks, %d tabs and %d newlines", bl= , t, nl); > > > > > > > > } by without an else if I just meant, if statements.

On Aug 13, 2:04=A0am, Seebs <usenet-nos...@seebs.net> wrote: > On 2011-08-13, Joseph Santoyo <josephsant...@gmail.com> wrote: > > > Is there any way to write this code without an else if? > > Sure! > > > If so how..and > > can you explain it line by line please :/ I'm really new to C or > > programming. > > Welcome! > > > /* count blanks, tabs and newlines in input */ > > main() > > You should probably spell this > =A0 =A0 =A0 =A0 int > =A0 =A0 =A0 =A0 main(void) > in modern C. > > > =A0 =A0 =A0 =A0 =A0 =A0if (c =3D=3D ' ') > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0++bl; > > =A0 =A0 =A0 =A0 =A0 =A0else if (c =3D=3D '\t') > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0++t; > > =A0 =A0 =A0 =A0 =A0 =A0else if (c =3D=3D '\n') > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0nl; > > (You missed the "++" on the last one; it should be "++nl".) > > You can write this without else if as follows: > > > =A0 =A0 =A0 =A0 =A0 =A0if (c =3D=3D ' ') > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0++bl; > > =A0 =A0 =A0 =A0 =A0 =A0if (c =3D=3D '\t') > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0++t; > > =A0 =A0 =A0 =A0 =A0 =A0if (c =3D=3D '\n') > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0++nl; > > It's not necessarily any better or more efficient, but it'll work. > > The way I'd probably do it would be: > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 switch (c) { > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 case ' ': ++bl; break; > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 case '\t': ++t; break; > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 case '\n': ++nl; break; > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 default: break; > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 } > > 'switch' jumps to a case matching the controlling expression, then execut= es > code until it hits a 'break'. =A0It's often relatively efficient for case= s > where there are many options; compilers may generate smarter code than fo= r > the corresponding sequence of else if ()s. > > > =A0 =A0printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl= ); > > ... and > =A0 =A0 =A0 =A0 return 0; > here. > > > } > > -s > -- > Copyright 2011, all wrongs reversed. =A0Peter Seebach / usenet-nos...@see= bs.nethttp://www.seebs.net/log/<-- lawsuits, religion, and funny picturesht= tp://en.wikipedia.org/wiki/Fair_Game_(Scientology) <-- get educated! > I am not speaking for my employer, although they do rent some of my opini= ons. Hey this is the second time you help me! Thanks a lot man :D!! Your explanations are very clear.

"Joseph Santoyo" <josephsantoyo@gmail.com> ha scritto nel messaggio news:4a72458c-aad4-4fa5-b3d5-9692eb2e470a@w18g2000yqc.googlegroups.com... > Is there any way to write this code without an else if? If so how..and > can you explain it line by line please :/ I'm really new to C or > programming. > > #include <stdio.h> > > /* count blanks, tabs and newlines in input */ > main() > { > int c, bl, t, nl; > > c = 0; > bl = 0; > t = 0; > nl = 0; > while ((c = getchar()) != EOF) > if (c == ' ') > ++bl; > else if (c == '\t') > ++t; > else if (c == '\n') > nl; > printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl); > } below it is the need to add "{}" because the many if #include <stdio.h> /* count blanks, tabs and newlines in input */ int main(void) {int c, bl, t, nl; bl=0; t=0; nl=0; while((c=getchar())!=EOF) {if(c== ' ' ) ++bl; if(c== '\t') ++t; if(c== '\n') ++nl; } printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl); } --------------------------- or #include <stdio.h> /* count blanks, tabs and newlines in input */ int main(void) {int c, bl, t, nl; bl=0; t=0; nl=0; while((c=getchar())!=EOF) {bl+=(c== ' ' ); t +=(c== '\t'); nl+=(c== '\n'); } printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl); } don't know if is garantee that if c==' ' it return 1 and not 90 it seems yes because i seen it here

On Aug 13, 3:03=A0am, "io_x" <a...@b.c.invalid> wrote: > "Joseph Santoyo" <josephsant...@gmail.com> ha scritto nel messaggionews:4= a72458c-aad4-4fa5-b3d5-9692eb2e470a@w18g2000yqc.googlegroups.com... > > > > > > > > > > > Is there any way to write this code without an else if? If so how..and > > can you explain it line by line please :/ I'm really new to C or > > programming. > > > #include <stdio.h> > > > /* count blanks, tabs and newlines in input */ > > main() > > { > > int c, bl, t, nl; > > > c =3D 0; > > bl =3D 0; > > t =3D 0; > > nl =3D 0; > > while ((c =3D getchar()) !=3D EOF) > > if (c =3D=3D ' ') > > ++bl; > > else if (c =3D=3D '\t') > > ++t; > > else if (c =3D=3D '\n') > > nl; > > printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl); > > } > > below =A0it is the need to add "{}" because the many if > > #include <stdio.h> > > /* count blanks, tabs and newlines in input */ > int =A0main(void) > {int c, bl, t, nl; > > =A0bl=3D0; t=3D0; nl=3D0; > =A0while((c=3Dgetchar())!=3DEOF) > =A0 =A0 {if(c=3D=3D ' ' ) ++bl; > =A0 =A0 =A0if(c=3D=3D '\t') ++t; > =A0 =A0 =A0if(c=3D=3D '\n') ++nl; > =A0 =A0 } > =A0printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl);} > > --------------------------- > or > #include <stdio.h> > > /* count blanks, tabs and newlines in input */ > int =A0main(void) > {int c, bl, t, nl; > > =A0bl=3D0; t=3D0; nl=3D0; > =A0while((c=3Dgetchar())!=3DEOF) > =A0 =A0 {bl+=3D(c=3D=3D ' ' ); > =A0 =A0 =A0t +=3D(c=3D=3D '\t'); > =A0 =A0 =A0nl+=3D(c=3D=3D '\n'); > =A0 =A0 } > =A0printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl); > > } > > don't know if is garantee that if c=3D=3D' ' it return 1 and not 90 > it seems yes because i seen it here Is it just as valid to put the ++bl, ++t, ++nl below the ifs?

Joseph Santoyo <josephsantoyo@gmail.com> writes: > On Aug 13, 2:10 am, Joseph Santoyo <josephsant...@gmail.com> wrote: >> Is there any way to write this code without an else if? If so how..and >> can you explain it line by line please :/ I'm really new to C or >> programming. >> >> #include <stdio.h> >> >> /* count blanks, tabs and newlines in input */ >> main() >> { >> int c, bl, t, nl; >> >> c = 0; >> bl = 0; >> t = 0; >> nl = 0; >> while ((c = getchar()) != EOF) >> if (c == ' ') >> ++bl; >> else if (c == '\t') >> ++t; >> else if (c == '\n') >> nl; >> printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl); >> } > > by without an else if I just meant, if statements. You can do it without any selection statements at all: while ((c = getchar() != EOF) { bl += (c == ' '); t += (c == '\n'); nl += (c == '\n'); } Not saying you *should*, but then I don't understand why you want to avoid "else if" in the first place! -- Ben.

Joseph Santoyo <josephsantoyo@gmail.com> writes: > Is there any way to write this code without an else if? If so how..and > can you explain it line by line please :/ I'm really new to C or > programming. > > #include <stdio.h> > > /* count blanks, tabs and newlines in input */ > main() > { > int c, bl, t, nl; > > c = 0; > bl = 0; > t = 0; > nl = 0; > while ((c = getchar()) != EOF) > if (c == ' ') > ++bl; > else if (c == '\t') > ++t; > else if (c == '\n') > nl; > printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl); > } // Disclaimer: not compiled #include <limits.h> #include <stdio.h> int main( void ){ int c; static int counts[ UCHAR_MAX ]; while( c = getchar(), c != EOF ) counts[c]++; printf( "There are %d blanks, %d tabs and %d newlines", counts[' '], counts['\t'], counts['\n'] ); return 0; }

On Fri, 12 Aug 2011 23:10:06 -0700, Joseph Santoyo wrote: > Is there any way to write this code without an else if? If so how..and > can you explain it line by line please :/ I'm really new to C or > programming. > > #include <stdio.h> > > /* count blanks, tabs and newlines in input */ main() > { > int c, bl, t, nl; > > c = 0; > bl = 0; > t = 0; > nl = 0; > while ((c = getchar()) != EOF) > if (c == ' ') > ++bl; > else if (c == '\t') > ++t; > else if (c == '\n') > nl; > printf("There are %d blanks, %d tabs and %d newlines", bl, t, nl); > } Just one thing that hasn't been mentioned yet: there's no need to give c an initial value of 0. -- Regards, Robert http://www.arumes.com

On Sun, 04 Sep 2011 13:04:47 -0700, Tim Rentsch <txr@alumni.caltech.edu> wrote: > Joseph Santoyo <josephsantoyo@gmail.com> writes: > > > Is there any way to write this code without an else if? If so how..and > > can you explain it line by line please :/ I'm really new to C or > > programming. > > > > #include <stdio.h> > > > > /* count blanks, tabs and newlines in input */ <snip> > int c; > static int counts[ UCHAR_MAX ]; > YM UCHAR_MAX+1 . > while( c = getchar(), c != EOF ) counts[c]++; > > printf( "There are %d blanks, %d tabs and %d newlines", > counts[' '], counts['\t'], counts['\n'] ); > Nit: int (same as the OP had) could overflow. But so could long, on many modern systems. unsigned int would make the results well-defined though still wrong, and probably at no additional cost (almost certainly undetectable beside the I/O cost anyway). For completeness, another answer to the OP's literal question is int c; /*unsigned?*/ int bl=0,t=0,nl=0, *p; while( c=getchar(), c!=EOF ){ p = c==' '? &bl: c=='\t'? &t: c=='\n'? &nl: NULL; if( p != NULL ) ++ *p; } printf /*as before or %u if unsigned*/ But really this is just 'else if' by another name.

David Thompson <dave.thompson2@verizon.net> writes: > On Sun, 04 Sep 2011 13:04:47 -0700, Tim Rentsch > <txr@alumni.caltech.edu> wrote: > >> Joseph Santoyo <josephsantoyo@gmail.com> writes: >> >> > Is there any way to write this code without an else if? If so how..and >> > can you explain it line by line please :/ I'm really new to C or >> > programming. >> > >> > #include <stdio.h> >> > >> > /* count blanks, tabs and newlines in input */ > <snip> >> int c; >> static int counts[ UCHAR_MAX ]; >> > YM UCHAR_MAX+1 . Thank you, yes I did. >> while( c = getchar(), c != EOF ) counts[c]++; >> >> printf( "There are %d blanks, %d tabs and %d newlines", >> counts[' '], counts['\t'], counts['\n'] ); >> > Nit: int (same as the OP had) could overflow. But so could long, > on many modern systems. unsigned int would make the results > well-defined though still wrong, and probably at no additional cost > (almost certainly undetectable beside the I/O cost anyway). > > For completeness, another answer to the OP's literal question is > int c; /*unsigned?*/ int bl=0,t=0,nl=0, *p; > while( c=getchar(), c!=EOF ){ > p = c==' '? &bl: c=='\t'? &t: c=='\n'? &nl: NULL; > if( p != NULL ) ++ *p; > } > printf /*as before or %u if unsigned*/ > > But really this is just 'else if' by another name. A similar approach, without any short circuiting: int c; unsigned long counts[4] = {0}; while( c=getchar(), c!=EOF ){ counts[ (c==' ')*1 + (c=='\t')*2 + (c=='\n')*3 ] += 1; } printf( "...appropriate format...", counts[1], counts[2], counts[3] );