What is wrong with this?

[Daniel Rudy]

What is wrong with this program? When I try to compile it, I get the
following error. Compiler is gcc on FreeBSD.

strata:/home/dcrudy/c 1055 $$$ ->cc -g -oe6-3 e6-3.c
e6-3.c: In function `main':
e6-3.c:32: syntax error before `||'
e6-3.c:33: syntax error before `printf'
e6-3.c:36: syntax error before `||'
e6-3.c:40: syntax error before `('
e6-3.c:40: syntax error before `strcpy'
e6-3.c:41: syntax error before `('
e6-3.c:41: syntax error before `strcpy'
e6-3.c:42: syntax error before `('
e6-3.c:42: syntax error before `strcpy'
e6-3.c:43: syntax error before `('
e6-3.c:43: syntax error before `strcpy'
e6-3.c:44: syntax error before `('
e6-3.c:44: syntax error before `strcpy'
e6-3.c:45: syntax error before `('
e6-3.c:45: syntax error before `strcpy'
e6-3.c:46: syntax error before `('
e6-3.c:46: syntax error before `strcpy'
e6-3.c:47: syntax error before `('
e6-3.c:47: syntax error before `strcpy'
e6-3.c:48: syntax error before `('
e6-3.c:48: syntax error before `strcpy'
e6-3.c:49: syntax error before `('
e6-3.c:49: syntax error before `strcpy'
e6-3.c:50: syntax error before `('
e6-3.c:50: syntax error before `strcpy'
e6-3.c:51: syntax error before `('
e6-3.c:51: syntax error before `strcpy'
strata:/home/dcrudy/c 1056 $$$ ->



/*

Programming Exercise 6-2: A professor generates letter
grades by the following values: 0-60 F, 61-70 D, 71-80 C,
81-90 B, 91-100 A. Given a numeric grade, print the
letter. Also print +, blank, or - using the following
values in the units place: 1-3 -, 4-7 blank, 8-0 +.

Page 93

*/

#include <stdio.h>
#include <string.h>

char line[100]; /* user data input line */
char cgrade[10]; /* character grade */
int ngrade; /* numeric grade */
int result; /* final results (computed) */

int main()
{

do
{

/* Get user input */
printf("Input numeric grade: ");
fgets(line, sizeof(line), stdin);
sscanf(line, "%d", &ngrade);

/* Check to make sure that input is valid */
if (ngrade < 0) || (ngrade > 100)
printf("Invalid Input: You must input a number between 0 and
100.\n");
else break;
}
while (ngrade < 0) || (ngrade > 100);

/* Now figure out what the letter grade is */
if (ngrade <= 60) strcpy(cgrade, "F");
if (ngrade >= 61) && (ngrade <= 63) strcpy(cgrade, "D-");
if (ngrade >= 64) && (ngrade <= 67) strcpy(cgrade, "D");
if (ngrade >= 68) && (ngrade <= 70) strcpy(cgrade, "D+");
if (ngrade >= 71) && (ngrade <= 73) strcpy(cgrade, "C-");
if (ngrade >= 74) && (ngrade <= 77) strcpy(cgrade, "C");
if (ngrade >= 78) && (ngrade <= 80) strcpy(cgrade, "C+");
if (ngrade >= 81) && (ngrade <= 83) strcpy(cgrade, "B-");
if (ngrade >= 84) && (ngrade <= 87) strcpy(cgrade, "B");
if (ngrade >= 88) && (ngrade <= 90) strcpy(cgrade, "B+");
if (ngrade >= 91) && (ngrade <= 93) strcpy(cgrade, "A-");
if (ngrade >= 94) && (ngrade <= 97) strcpy(cgrade, "A");
if (ngrade >= 98) && (ngrade <= 100) strcpy(cgrade, "A+");

/* Print the results */
printf("Letter grade is %s.\n", cgrade);
return(0);
}

 

[Leor Zolman]

What is wrong with this program? When I try to compile it, I get the
following error. Compiler is gcc on FreeBSD.

When you have multiple conditions, for any conditional expression, they
must all be enclosed within an "outer" pair of parens. IOW,
if (blah) && (blah) : no good
if (blah && blah): ok
if ((blah) && (blah)): also OK (but usually unnecessary due to
precedence.)

Same for whiles.
-leor

 

[Mark A. Odell]

What is wrong with this program? When I try to compile it, I get the
following error. Compiler is gcc on FreeBSD.

strata:/home/dcrudy/c 1055 $$$ ->cc -g -oe6-3 e6-3.c
e6-3.c: In function `main':
e6-3.c:32: syntax error before `||'
e6-3.c:33: syntax error before `printf'
e6-3.c:36: syntax error before `||'
e6-3.c:40: syntax error before `('
e6-3.c:40: syntax error before `strcpy'
e6-3.c:41: syntax error before `('
e6-3.c:41: syntax error before `strcpy'
e6-3.c:42: syntax error before `('
e6-3.c:42: syntax error before `strcpy'
e6-3.c:43: syntax error before `('
e6-3.c:43: syntax error before `strcpy'
e6-3.c:44: syntax error before `('
e6-3.c:44: syntax error before `strcpy'
e6-3.c:45: syntax error before `('
e6-3.c:45: syntax error before `strcpy'
e6-3.c:46: syntax error before `('
e6-3.c:46: syntax error before `strcpy'
e6-3.c:47: syntax error before `('
e6-3.c:47: syntax error before `strcpy'
e6-3.c:48: syntax error before `('
e6-3.c:48: syntax error before `strcpy'
e6-3.c:49: syntax error before `('
e6-3.c:49: syntax error before `strcpy'
e6-3.c:50: syntax error before `('
e6-3.c:50: syntax error before `strcpy'
e6-3.c:51: syntax error before `('
e6-3.c:51: syntax error before `strcpy'
strata:/home/dcrudy/c 1056 $$$ ->



/*

Programming Exercise 6-2: A professor generates letter
grades by the following values: 0-60 F, 61-70 D, 71-80 C,
81-90 B, 91-100 A. Given a numeric grade, print the
letter. Also print +, blank, or - using the following
values in the units place: 1-3 -, 4-7 blank, 8-0 +.

Page 93

*/

#include <stdio.h>
#include <string.h>

char line[100]; /* user data input line */
char cgrade[10]; /* character grade */
int ngrade; /* numeric grade */
int result; /* final results (computed) */

int main()
{

do
{

/* Get user input */
printf("Input numeric grade: ");
fgets(line, sizeof(line), stdin);
sscanf(line, "%d", &ngrade);

/* Check to make sure that input is valid */
if (ngrade < 0) || (ngrade > 100)

if (ngrade < 0 || ngrade > 100)
-- or --
if ((ngrade < 0 || ngrade > 100))

Two extra parens, or, two too few parens.

 

[Mark A. Odell]

if (ngrade < 0 || ngrade > 100)
-- or --
if ((ngrade < 0) || (ngrade > 100))

Ahem.

 

[Daniel Rudy]

And somewhere around the time of 05/18/2004 10:07, the world stopped and
listened as Leor Zolman contributed the following to humanity:

When you have multiple conditions, for any conditional expression, they
must all be enclosed within an "outer" pair of parens. IOW,
if (blah) && (blah) : no good
if (blah && blah): ok
if ((blah) && (blah)): also OK (but usually unnecessary due to
precedence.)

Same for whiles.
-leor

Ah, I see. The book has the following format:

if (expression)
statement;
else
statement;

Which is sorta confusing at first glance, but it makes sense now. Thank
you for the reply.

 

[Leor Zolman]

And somewhere around the time of 05/18/2004 10:07, the world stopped and
listened as Leor Zolman contributed the following to humanity:

I'd love to be inside someone's mind when they see the above snippet in a
Google Groups search result ;-)

Ah, I see. The book has the following format:

if (expression)
statement;
else
statement;

Which is sorta confusing at first glance, but it makes sense now. Thank
you for the reply.

No prob,
-leor

 

[Martin Ambuhl]

What is wrong with this program? When I try to compile it, I get the
following error. Compiler is gcc on FreeBSD.

strata:/home/dcrudy/c 1055 $$$ ->cc -g -oe6-3 e6-3.c
e6-3.c: In function `main':
e6-3.c:32: syntax error before `||'
e6-3.c:33: syntax error before `printf' [...]

if (ngrade < 0) || (ngrade > 100)
printf("Invalid Input: You must input a number between 0 and
100.\n");

[...]

A selection-statement is one of
if ( expression ) statement
if ( expression ) statement else statement
switch ( expression ) statement
and
The controlling expression of an if statement shall have scalar type.

For your code

> if (ngrade < 0) || (ngrade > 100)

to be right,
ngrade < 0) || (ngrade > 100
would have to be an expression. It is not.
ngrade < 0 || ngrade > 100
and
(ngrade < 0) || (ngrade > 100)
are expressions, yielding the if-statements
if (ngrade < 0 || ngrade > 100) { /* statement */ }
and
if ((ngrade < 0) || (ngrade > 100)) { /* statement */ }

The error on the next line is a "cascading error", the result of an
attempt to parse the broken line before it. Unless, of course, the
end-of-line between 'and' and '100' is in the original and not an
artifact of newsposting software.