问题
Really basic program in C, but I'm getting the following error:
tcc: error: undefined symbol 'GetFloat'
What's the problem and how do I fix it? I placed cs50.c and cs50.h into the same directory as my script. The following is my main file:
#include "cs50.h"
#include <stdio.h>
int main(void)
{
printf("enter change owed: ");
float x = GetFloat();
printf("you entered %f\n", x);
}
Here's cs50.h
/****************************************************************************
* CS50 Library 4
* https://manual.cs50.net/Library
*
* Based on Eric Roberts' genlib.c and simpio.c.
*
* Copyright (c) 2011,
* Glenn Holloway <holloway@eecs.harvard.edu>
* David J. Malan <malan@harvard.edu>
* All rights reserved.
*
* BSD 3-Clause License
* http://www.opensource.org/licenses/BSD-3-Clause
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of CS50 nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
***************************************************************************/
#ifndef _CS50_H
#define _CS50_H
#include <float.h>
#include <limits.h>
#include <stdbool.h>
#include <stdlib.h>
/*
* Our own data type for string variables.
*/
typedef char *string;
/*
* Reads a line of text from standard input and returns the equivalent
* char; if text does not represent a char, user is prompted to retry.
* Leading and trailing whitespace is ignored. If line can't be read,
* returns CHAR_MAX.
*/
char GetChar(void);
/*
* Reads a line of text from standard input and returns the equivalent
* double as precisely as possible; if text does not represent a
* double, user is prompted to retry. Leading and trailing whitespace
* is ignored. For simplicity, overflow and underflow are not detected.
* If line can't be read, returns DBL_MAX.
*/
double GetDouble(void);
/*
* Reads a line of text from standard input and returns the equivalent
* float as precisely as possible; if text does not represent a float,
* user is prompted to retry. Leading and trailing whitespace is ignored.
* For simplicity, overflow and underflow are not detected. If line can't
* be read, returns FLT_MAX.
*/
float GetFloat(void);
/*
* Reads a line of text from standard input and returns it as an
* int in the range of [-2^31 + 1, 2^31 - 2], if possible; if text
* does not represent such an int, user is prompted to retry. Leading
* and trailing whitespace is ignored. For simplicity, overflow is not
* detected. If line can't be read, returns INT_MAX.
*/
int GetInt(void);
/*
* Reads a line of text from standard input and returns an equivalent
* long long in the range [-2^63 + 1, 2^63 - 2], if possible; if text
* does not represent such a long long, user is prompted to retry.
* Leading and trailing whitespace is ignored. For simplicity, overflow
* is not detected. If line can't be read, returns LLONG_MAX.
*/
long long GetLongLong(void);
/*
* Reads a line of text from standard input and returns it as a
* string (char *), sans trailing newline character. (Ergo, if
* user inputs only "\n", returns "" not NULL.) Returns NULL
* upon error or no input whatsoever (i.e., just EOF). Leading
* and trailing whitespace is not ignored. Stores string on heap
* (via malloc); memory must be freed by caller to avoid leak.
*/
string GetString(void);
#endif
and lastly, here's cs50.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "cs50.h"
/*
* Reads a line of text from standard input and returns the equivalent
* char; if text does not represent a char, user is prompted to retry.
* Leading and trailing whitespace is ignored. If line can't be read,
* returns CHAR_MAX.
*/
char GetChar(void)
{
// try to get a char from user
while (true)
{
// get line of text, returning CHAR_MAX on failure
string line = GetString();
if (line == NULL)
return CHAR_MAX;
// return a char if only a char (possibly with
// leading and/or trailing whitespace) was provided
char c1, c2;
if (sscanf(line, " %c %c", &c1, &c2) == 1)
{
free(line);
return c1;
}
else
{
free(line);
printf("Retry: ");
}
}
}
/*
* Reads a line of text from standard input and returns the equivalent
* double as precisely as possible; if text does not represent a
* double, user is prompted to retry. Leading and trailing whitespace
* is ignored. For simplicity, overflow and underflow are not detected.
* If line can't be read, returns DBL_MAX.
*/
double GetDouble(void)
{
// try to get a double from user
while (true)
{
// get line of text, returning DBL_MAX on failure
string line = GetString();
if (line == NULL)
return DBL_MAX;
// return a double if only a double (possibly with
// leading and/or trailing whitespace) was provided
double d; char c;
if (sscanf(line, " %lf %c", &d, &c) == 1)
{
free(line);
return d;
}
else
{
free(line);
printf("Retry: ");
}
}
}
/*
* Reads a line of text from standard input and returns the equivalent
* float as precisely as possible; if text does not represent a float,
* user is prompted to retry. Leading and trailing whitespace is ignored.
* For simplicity, overflow and underflow are not detected. If line can't
* be read, returns FLT_MAX.
*/
float GetFloat(void)
{
// try to get a float from user
while (true)
{
// get line of text, returning FLT_MAX on failure
string line = GetString();
if (line == NULL)
return FLT_MAX;
// return a float if only a float (possibly with
// leading and/or trailing whitespace) was provided
char c; float f;
if (sscanf(line, " %f %c", &f, &c) == 1)
{
free(line);
return f;
}
else
{
free(line);
printf("Retry: ");
}
}
}
/*
* Reads a line of text from standard input and returns it as an
* int in the range of [-2^31 + 1, 2^31 - 2], if possible; if text
* does not represent such an int, user is prompted to retry. Leading
* and trailing whitespace is ignored. For simplicity, overflow is not
* detected. If line can't be read, returns INT_MAX.
*/
int GetInt(void)
{
// try to get an int from user
while (true)
{
// get line of text, returning INT_MAX on failure
string line = GetString();
if (line == NULL)
return INT_MAX;
// return an int if only an int (possibly with
// leading and/or trailing whitespace) was provided
int n; char c;
if (sscanf(line, " %d %c", &n, &c) == 1)
{
free(line);
return n;
}
else
{
free(line);
printf("Retry: ");
}
}
}
/*
* Reads a line of text from standard input and returns an equivalent
* long long in the range [-2^63 + 1, 2^63 - 2], if possible; if text
* does not represent such a long long, user is prompted to retry.
* Leading and trailing whitespace is ignored. For simplicity, overflow
* is not detected. If line can't be read, returns LLONG_MAX.
*/
long long GetLongLong(void)
{
// try to get a long long from user
while (true)
{
// get line of text, returning LLONG_MAX on failure
string line = GetString();
if (line == NULL)
return LLONG_MAX;
// return a long long if only a long long (possibly with
// leading and/or trailing whitespace) was provided
long long n; char c;
if (sscanf(line, " %lld %c", &n, &c) == 1)
{
free(line);
return n;
}
else
{
free(line);
printf("Retry: ");
}
}
}
/*
* Reads a line of text from standard input and returns it as a
* string (char*), sans trailing newline character. (Ergo, if
* user inputs only "\n", returns "" not NULL.) Returns NULL
* upon error or no input whatsoever (i.e., just EOF). Leading
* and trailing whitespace is not ignored. Stores string on heap
* (via malloc); memory must be freed by caller to avoid leak.
*/
string GetString(void)
{
// growable buffer for chars
string buffer = NULL;
// capacity of buffer
unsigned int capacity = 0;
// number of chars actually in buffer
unsigned int n = 0;
// character read or EOF
int c;
// iteratively get chars from standard input
while ((c = fgetc(stdin)) != '\n' && c != EOF)
{
// grow buffer if necessary
if (n + 1 > capacity)
{
// determine new capacity: start at 32 then double
if (capacity == 0)
capacity = 32;
else if (capacity <= (UINT_MAX / 2))
capacity *= 2;
else
{
free(buffer);
return NULL;
}
// extend buffer's capacity
string temp = realloc(buffer, capacity * sizeof(char));
if (temp == NULL)
{
free(buffer);
return NULL;
}
buffer = temp;
}
// append current character to buffer
buffer[n++] = c;
}
// return NULL if user provided no input
if (n == 0 && c == EOF)
return NULL;
// minimize buffer
string minimal = malloc((n + 1) * sizeof(char));
strncpy(minimal, buffer, n);
free(buffer);
// terminate string
minimal[n] = '\0';
// return string
return minimal;
}
回答1:
Your code is fine. I am not familiar with tcc, but the error you get seems not related to your #include "cs50.h", which is correct. From what i understand, your issue is related to linking.
You need to tell tcc to first build an intermediate file from cs50.c and cs50.h
Here's how i would compile your program with gcc:
gcc -c cs50.c //creates an object usually named cs50.o
gcc cs50.o grdy.c -o grdy.exe //links all together to build the executable (this expects the main to be in grdy.c)
Hope this helps.
来源：https://stackoverflow.com/questions/15214170/importing-c-library-in-windows