代码问题 [英] code question
问题描述
我有这个代码我想清理。
#include< stdio.h>
#include< stdlib.h>
int main（int argc，char * argv []）
{
double x，y，a，b;
FILE * fp;
x = strtod（argv [1]，NULL）;
y = strtod（argv [2]，NULL）;
a = strtod（argv [3]，NULL）;
b = strtod（argv [4]，NULL）;
if（（fp） = fopen（argv [4]，a））== NULL）{
puts（fopen error）;
exit（-1）;
}
fprintf（fp，"％。2f \ t％。2f \ t％。2f \ t％。2f \ n"，x ，y，a，b）;
if（fclose（fp）== EOF）{
puts（fclose error）;
退出（-1）;
}
返回0;
}
如果程序运行没有参数我得到一个seg错误。如果用
4运行，没问题。如果它运行少于四个（包括argv [0]）那么
程序不想运行正确。我怎么能用这个
程序说一两个argv？
比尔
I have this code I would like to clean up.
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
double x, y, a, b;
FILE *fp;
x = strtod(argv[1], NULL);
y = strtod(argv[2], NULL);
a = strtod(argv[3], NULL);
b = strtod(argv[4], NULL);
if ((fp = fopen(argv[4], "a")) == NULL) {
puts("fopen error");
exit(-1);
}
fprintf(fp, "%.2f\t%.2f\t%.2f\t%.2f\n", x, y, a, b);
if (fclose(fp) == EOF) {
puts("fclose error");
exit(-1);
}
return 0;
}
If the program is run with no arguments I get a seg fault. If it is run with
4, no problem. If it is run with less than four (that includes argv[0]) then
the program doesn''t want to run right. How would I be able to use this
program with say one or two argvs ?
Bill
推荐答案
Bill Cunningham说：
Bill Cunningham said:
我有这个代码我想清理。
#include< stdio.h>
#include< stdlib.h>
int main（int argc，char * argv []）
{
双x，y，a，b;
FILE * fp;
x = strtod（argv [ 1]，NULL）;
y = strtod（argv [2]，NULL）;
a = strtod（argv [3]，NULL）;
b = strtod（argv [4]，NULL）;
if（（fp = fopen（argv [4]，" a"））== NULL）{
put（fopen error）;
退出（-1）;
}
fprintf（fp，"％。 2f \t％。2f \ t％。2f \ t％。2f \ n"，x，y，a，b）;
if（fclose（fp）== EOF ）{
puts（fclose error）;
退出（-1）;
}
返回0;
}
如果程序运行时没有参数，我会遇到段错误。如果运行
4，没问题。如果它运行少于四个（包括
argv [0]）那么程序不想运行正确。我怎么能用这个程序说一两个argv？
？
I have this code I would like to clean up.
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
double x, y, a, b;
FILE *fp;
x = strtod(argv[1], NULL);
y = strtod(argv[2], NULL);
a = strtod(argv[3], NULL);
b = strtod(argv[4], NULL);
if ((fp = fopen(argv[4], "a")) == NULL) {
puts("fopen error");
exit(-1);
}
fprintf(fp, "%.2f\t%.2f\t%.2f\t%.2f\n", x, y, a, b);
if (fclose(fp) == EOF) {
puts("fclose error");
exit(-1);
}
return 0;
}
If the program is run with no arguments I get a seg fault. If it is run
with 4, no problem. If it is run with less than four (that includes
argv[0]) then the program doesn''t want to run right. How would I be able
to use this program with say one or two argvs ?
#include< stdio.h>
#include< stdlib.h>
#define DEFAULT_FILE_NAME" foo.bar"
int main（int argc，char * argv []）
{
double x = 0.0，y = 0.0，a = 0.0，b = 0.0;
const char * filename = DEFAULT_FILE_NAME;
FILE * fp = NULL;
if（argc 1）
{
x = strtod（argv [1]，NULL）;
}
if（argc 2）
{
y = strtod（argv [2]，NULL）;
}
if（argc 3）
{
a = strtod（argv [3]，NULL）;
}
if（argc 4）
{
b = strtod（argv [4]，NULL）;
filename = argv [4];
}
if（（fp = fopen（filename，" a"））== NULL）{
puts（fopen error）;
退出（EXIT_FAILURE）;
}
fprintf（fp，"％。 2f\t％。2f \ t％。2f \ t％。2f \ n"，x，y，a，b）;
if（fclo se（fp）== EOF）{
put（fclose error）;
退出（EXIT_FAILURE）;
}
返回0;
}
-
Richard Heathfield< http：// www。 cpax.org.uk>
电子邮件：-http：// www。 + rjh @
谷歌用户：< http://www.cpax.org.uk/prg/writings/googly.php>
Usenet是一个奇怪的放置" - dmr 1999年7月29日
#include <stdio.h>
#include <stdlib.h>
#define DEFAULT_FILE_NAME "foo.bar"
int main(int argc, char *argv[])
{
double x = 0.0, y = 0.0, a = 0.0, b = 0.0;
const char *filename = DEFAULT_FILE_NAME;
FILE *fp = NULL;
if(argc 1)
{
x = strtod(argv[1], NULL);
}
if(argc 2)
{
y = strtod(argv[2], NULL);
}
if(argc 3)
{
a = strtod(argv[3], NULL);
}
if(argc 4)
{
b = strtod(argv[4], NULL);
filename = argv[4];
}
if ((fp = fopen(filename, "a")) == NULL) {
puts("fopen error");
exit(EXIT_FAILURE);
}
fprintf(fp, "%.2f\t%.2f\t%.2f\t%.2f\n", x, y, a, b);
if (fclose(fp) == EOF) {
puts("fclose error");
exit(EXIT_FAILURE);
}
return 0;
}
--
Richard Heathfield <http://www.cpax.org.uk>
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999
Bill Cunningham写道：
Bill Cunningham wrote:
我有这个代码我想清理。
#include< stdio.h>
#include< stdlib.h>
int main（int argc，char * argv []）
{
double x，y，a，b;
FILE * fp;
x = strtod（argv [1]，NULL）;
y = strtod（argv [2]，NULL）;
a = strtod（argv [ 3]，NULL）;
b = strtod（argv [4]，NULL）;
if（（fp = fopen（argv [4]，" a"） ）== NULL）{
puts（fopen error）;
退出（-1）;
}
fprintf（fp，"％。2f \ t％。2f \ t％。2f \ t％。2f \ n"，x，y，a，b）;
if（fclose（fp）== EOF）{
puts（fclose error）;
exit（-1）;
}
返回0;
}
如果是e程序运行没有参数我得到一个seg错误。如果用
4运行，没问题。如果它运行少于四个（包括argv [0]）那么
程序不想运行正确。我怎么能用这个
程序说一两个argv？
I have this code I would like to clean up.
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
double x, y, a, b;
FILE *fp;
x = strtod(argv[1], NULL);
y = strtod(argv[2], NULL);
a = strtod(argv[3], NULL);
b = strtod(argv[4], NULL);
if ((fp = fopen(argv[4], "a")) == NULL) {
puts("fopen error");
exit(-1);
}
fprintf(fp, "%.2f\t%.2f\t%.2f\t%.2f\n", x, y, a, b);
if (fclose(fp) == EOF) {
puts("fclose error");
exit(-1);
}
return 0;
}
If the program is run with no arguments I get a seg fault. If it is run with
4, no problem. If it is run with less than four (that includes argv[0]) then
the program doesn''t want to run right. How would I be able to use this
program with say one or two argvs ?
你的要求不完整。
如果参数少于四个，会发生什么？应该打开一个文件
吗？是否应输出错误信息？
如果没有这些细节，可能存在许多相互矛盾的解决方案。
-
Ian Collins。
Your requirements are incomplete.
What should happen if there are less than four arguments? Should a file
be opened? Should an error message be output?
Without these details, there a number of conflicting possible solutions.
--
Ian Collins.
" Richard Heathfield" < rj*@see.sig.invalidwrote in message
news：wL ********************* @ bt.com .. 。
"Richard Heathfield" <rj*@see.sig.invalidwrote in message
news:wL*********************@bt.com...
#include< stdio.h>
#include< stdlib.h>
#define DEFAULT_FILE_NAME" foo.bar"
int main（int argc，char * argv []）
{
double x = 0.0，y = 0.0，a = 0.0，b = 0.0;
const char * filename = DEFAULT_FILE_NAME;
FILE * fp = NULL;
if（argc 1）
{
x = strtod（argv [1]，NULL）;
}
if（argc 2）
{
y = strtod（argv [2]，NULL）;
}
if（argc 3）
{
a = strtod（argv [3]，NULL）;
}
if（argc 4）
{
b = strtod（argv [4]，NULL）;
filename = argv [4];
}
if（（fp = fopen（filename，" a"））== NULL）{
pu ts（fopen error）;
退出（EXIT_FAILURE）;
}
fprintf（fp，"％。2f \ t％.2f \ t％。2f \ t％。2f \ n"，x，y，a，b）;
if（fclose（fp）== EOF）{
put（fclose error）;
退出（EXIT_FAILURE）;
}
返回0; < br $>
}
#include <stdio.h>
#include <stdlib.h>
#define DEFAULT_FILE_NAME "foo.bar"
int main(int argc, char *argv[])
{
double x = 0.0, y = 0.0, a = 0.0, b = 0.0;
const char *filename = DEFAULT_FILE_NAME;
FILE *fp = NULL;
if(argc 1)
{
x = strtod(argv[1], NULL);
}
if(argc 2)
{
y = strtod(argv[2], NULL);
}
if(argc 3)
{
a = strtod(argv[3], NULL);
}
if(argc 4)
{
b = strtod(argv[4], NULL);
filename = argv[4];
}
if ((fp = fopen(filename, "a")) == NULL) {
puts("fopen error");
exit(EXIT_FAILURE);
}
fprintf(fp, "%.2f\t%.2f\t%.2f\t%.2f\n", x, y, a, b);
if (fclose(fp) == EOF) {
puts("fclose error");
exit(EXIT_FAILURE);
}
return 0;
}
谢谢理查德我知道我总是可以依靠你。我想知道argc
及其用途。
Bill
Thanks Richard I know I can always count on you. I wondered about argc
and its uses.
Bill
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