truncated c语言（C语言while循环里使用scanf（）获取键盘输入，执行循环scanf（）在循坏开头还是结尾是不是有很大区别）

本文目录

• C语言while循环里使用scanf()获取键盘输入，执行循环scanf()在循坏开头还是结尾是不是有很大区别
• c语言的困惑
• c语言printf中%g的含义是什么代码如下
• Python创建文件时为什么会提示an interger is required，.py文件跟创建
• 急求C语言头文件源代码!!~~
• C语言格式输出问题
• C语言选啥呀
• GetModuleFileName() C语言问题

C语言while循环里使用scanf()获取键盘输入，执行循环scanf()在循坏开头还是结尾是不是有很大区别

你的问题并未说清楚。在你这个循环里，不能放在12行后面。因为while(sec》0)中要判断sec是否大于0，如果放在12行后面那么sec被后面的语句改变以了的话，就有问题了。另外，因为while前有一句scanf("%d",&sec);，12行后面再scanf("%d",&sec);的话不是两个语句重复了？若去掉while前的scanf("%d",&sec);，那么第一次进入while(sec》0)时sec还没有赋值，则要出错。所以这段代码的结构决定了scanf("%d",&sec);放在while循环的最后是合理的。放在什么地方是代码结构决定的，并不是while中的scanf("%d",&sec);一定要放在最后……

c语言的困惑

The type character is the only required format field; it appears after any optional format fields. The type character determines whether the associated argument is interpreted as a character, string, or number. The types C, n, p, and S, and the behavior of c and s with printf functions, are Microsoft extensions and are not ANSI compatible. Character Type Output format c int or wint_t When used with printf functions, specifies a single-byte character; when used with wprintf functions, specifies a wide character. C int or wint_t When used with printf functions, specifies a wide character; when used with wprintf functions, specifies a single-byte character. d int Signed decimal integer. i int Signed decimal integer. o int Unsigned octal integer. u int Unsigned decimal integer. x int Unsigned hexadecimal integer, using "abcdef." X int Unsigned hexadecimal integer, using "ABCDEF." e double Signed value having the form is two or three decimal digits depending on the output format and size of the exponent, and sign is + or –. E double Identical to the e format except that E rather than e introduces the exponent. f double Signed value having the form dddd.dddd, where dddd is one or more decimal digits. The number of digits before the decimal point depends on the magnitude of the number, and the number of digits after the decimal point depends on the requested precision. g double Signed value printed in f or e format, whichever is more compact for the given value and precision. The e format is used only when the exponent of the value is less than –4 or greater than or equal to the precision argument. Trailing zeros are truncated, and the decimal point appears only if one or more digits follow it. G double Identical to the g format, except that E, rather than e, introduces the exponent (where appropriate). a double Signed hexadecimal double precision floating point value having the form 0xh.hhhh p±dd, where h.hhhh are the hex digits (using lower case letters) of the mantissa, and dd are one or more digits for the exponent. The precision specifies the number of digits after the point. A double Signed hexadecimal double precision floating point value having the form 0Xh.hhhh P±dd, where h.hhhh are the hex digits (using capital letters) of the mantissa, and dd are one or more digits for the exponent. The precision specifies the number of digits after the point. n Pointer to integer Number of characters successfully written so far to the stream or buffer; this value is stored in the integer whose address is given as the argument. See Security Note below. p Pointer to void Prints the argument as an address in hexadecimal digits. s String When used with printf functions, specifies a single-byte–character string; when used with wprintf functions, specifies a wide-character string. Characters are printed up to the first null character or until the precision value is reached. S String When used with printf functions, specifies a wide-character string; when used with wprintf functions, specifies a single-byte–character string. Characters are printed up to the first null character or until the precision value is reached. 这是vc中的应该和c是通用的 MSDN很好用 可以去下载个

c语言printf中%g的含义是什么代码如下

转换说明及作为结果的打印输出％a 浮点数、十六进制数字和p-记数法（C99）%A 浮点数、十六进制数字和p-记法（C99）%c 一个字符 %d 有符号十进制整数 %e 浮点数、e-记数法%E 浮点数、E-记数法%f 浮点数、十进制记数法 %g 根据数值不同自动选择％f或％e．%G 根据数值不同自动选择％f或％e.%i 有符号十进制数（与％d相同）%o 无符号八进制整数%p 指针 %s 字符串%u 无符号十进制整数%x 使用十六进制数字0f的无符号十六进制整数 %X 使用十六进制数字0f的无符号十六进制整数%% 打印一个百分号 使用printf ()函数 printf()的基本形式： printf("格式控制字符串"，变量列表);

Python创建文件时为什么会提示an interger is required，.py文件跟创建

你的open函数不对啊。感觉象是你不小心重载了open函数。导致open不再是打开文件用的那个open. 感觉你象是用了一个python的扩展库，它的open函数用的很象是C语言的open. 而不是python标准的。

》》》 f=open("d:/1.txt",’w’)》》》 f.write(’ddd’)》》》 f.close()》》》

我试过了没有什么问题。

你需要把原代码完整的打出来

顺便说一下。不要使用中文目录。要全英文目录，目录中也不准有空格。如果你老师就这么教你的，说明他没有用过老版本的python。也很少用其它英文软件。

你再运行help(open)试试看

》》》 help(open)Help on built-in function open in module __builtin__:open(...)    open(name) -》 file object    Open a file using the file() type, returns a file object.  This is the    preferred way to open a file.  See file.__doc__ for further information.》》》》》》 print file.__doc__file(name) -》 file objectOpen a file.  The mode can be ’r’, ’w’ or ’a’ for reading (default),writing or appending.  The file will be created if it doesn’t existwhen opened for writing or appending; it will be truncated whenopened for writing.  Add a ’b’ to the mode for binary files.Add a ’+’ to the mode to allow simultaneous reading and writing.If the buffering argument is given, 0 means unbuffered, 1 means linebuffered, and larger numbers specify the buffer size.  The preferred wayto open a file is with the builtin open() function.Add a ’U’ to mode to open the file for input with universal newlinesupport.  Any line ending in the input file will be seen as a ’\n’in Python.  Also, a file so opened gains the attribute ’newlines’;the value for this attribute is one of None (no newline read yet),’\r’, ’\n’, ’\r\n’ or a tuple containing all the newline types seen.’U’ cannot be combined with ’w’ or ’+’ mode.

第三个参数是需要整型的。你是不是少写了什么。

急求C语言头文件源代码!!~~

#ifndef POSTGRES_SQLCA_H#define POSTGRES_SQLCA_H#ifndef DLLIMPORT#ifdef __CYGWIN__#define DLLIMPORT __declspec (dllimport)#else#define DLLIMPORT#endif /* __CYGWIN__ */#endif /* DLLIMPORT */#define SQLERRMC_LEN 70#ifdef __cplusplusextern "C"{#endifstruct sqlca{ char sqlcaid; long sqlabc; long sqlcode; struct { int sqlerrml; char sqlerrmc; } sqlerrm; char sqlerrp; long sqlerrd; /* Element 0: empty */ /* 1: OID of processed tuple if applicable */ /* 2: number of rows processed */ /* after an INSERT, UPDATE or */ /* DELETE statement */ /* 3: empty */ /* 4: empty */ /* 5: empty */ char sqlwarn; /* Element 0: set to ’W’ if at least one other is ’W’ */ /* 1: if ’W’ at least one character string */ /* value was truncated when it was */ /* stored into a host variable. */ /* * 2: if ’W’ a (hopefully) non-fatal notice occured */ /* 3: empty */ /* 4: empty */ /* 5: empty */ /* 6: empty */ /* 7: empty */ char sqlext;};extern DLLIMPORT struct sqlca sqlca;#ifdef __cplusplus}#endif#endif

C语言格式输出问题

%4.3中的4描述的是printf的输出至少有4个字符，而你的3.142超出了4个字符，根据printf的规定，%4.3中的4就不起总用了，要服从于3.142的具体长度，为啥从1415变成142了呢？这时因为%4.3中,点后面的3描述的是小数后的精度，要三位，所以就是三位。兄弟，要多看MSDN。参考自MSDN6.0：printf Width SpecificationThe second optional field of the format specification is the width specification. The width argument is a nonnegative decimal integer controlling the minimum number of characters printed. If the number of characters in the output value is less than the specified width, blanks are added to the left or the right of the values — depending on whether the – flag (for left alignment) is specified — until the minimum width is reached. If width is prefixed with 0, zeros are added until the minimum width is reached (not useful for left-aligned numbers).The width specification never causes a value to be truncated. If the number of characters in the output value is greater than the specified width, or if width is not given, all characters of the value are printed (subject to the precision specification).If the width specification is an asterisk (*), an int argument from the argument list supplies the value. The width argument must precede the value being formatted in the argument list. A nonexistent or small field width does not cause the truncation of a field; if the result of a conversion is wider than the field width, the field expands to contain the conversion result.

C语言选啥呀

你好，

答案选D，

man手册的描述如下。

NAME

fopen, fdopen, freopen - stream open functions  

SYNOPSIS

#include 《stdio.h》

FILE *fopen(const char *path, const char *mode); FILE *fdopen(int fildes, const char *mode); FILE *freopen(const char *path, const char *mode, FILE *stream);  

DESCRIPTION

The fopen() function opens the file whose name is the string pointed to by path and associates a stream with it.

The argument mode points to a string beginning with one of the following sequences (Additional characters may follow these sequences.):

• r

• Open text file for reading. The stream is positioned at the beginning of the file.

• r+

• Open for reading and writing. The stream is positioned at the beginning of the file.

• w

• Truncate file to zero length or create text file for writing. The stream is positioned at the beginning of the file.

• w+

• Open for reading and writing. The file is created if it does not exist, otherwise it is truncated. The stream is positioned at the beginning of the file.

• a

• Open for appending (writing at end of file). The file is created if it does not exist. The stream is positioned at the end of the file.

• a+

• Open for reading and appending (writing at end of file). The file is created if it does not exist. The initial file position for reading is at the beginning of the file, but output is always appended to the end of the file. 

• 祝你生活愉快。

GetModuleFileName() C语言问题

首先，这是一个Win32的API，必须使用Win32的编译器，用VC++还行，TC就算了。然后，包含windows.h头文件，函数原型如下：DWORD GetModuleFileName( HMODULE hModule, // handle to module to find filename for LPTSTR lpFilename, // pointer to buffer to receive module path DWORD nSize // size of buffer, in characters); ParametershModule Handle to the module whose executable filename is being requested. If this parameter is NULL, GetModuleFileName returns the path for the file used to create the calling process. lpFilename Pointer to a buffer that is filled in with the path and filename of the given module. nSize Specifies the length, in characters, of the lpFilename buffer. If the length of the path and filename exceeds this limit, the string is truncated. Return ValuesIf the function succeeds, the return value is the length, in characters, of the string copied to the buffer.If the function fails, the return value is zero. To get extended error information, call GetLastError.