怎么从一个txt文件里把数据读出来

[蒙哥卡恩]

我有一个txt文件，然后有一个计算拟合曲线的函数，我想把txt文件里的数据读出来到函数里进行运算怎么弄，求代码指教

[蒙哥卡恩]

引用 6 楼 zhao4zhong1 的回复:

11行
if (NULL==fgets(ln,100,f)) breakl
应改为
if (NULL==fgets(ln,100,f)) break;

[蒙哥卡恩]

引用 6 楼 zhao4zhong1 的回复:

11行
if (NULL==fgets(ln,100,f)) breakl
应改为
if (NULL==fgets(ln,100,f)) break;

打开的不是我的文件里的数据，全是零，怎么弄啊大神

[蒙哥卡恩]

who can help me?

[candeabc123]

你先去看看文件读写怎么做的先

[赵4老师]

12行sscanf("%*s%d:00,%lf",&h[i],&d[i]); 应改为 sscanf(ln,"%*s%d:00,%lf",&h[i],&d[i]);

//in.txt:
//2013/11/1 0:00,0.76
//2013/11/1 12:00,0.87
#include <stdio.h>
FILE *f;
char ln[100];
int h[200];
double d[200];
int i,n;
int main() {
    f=fopen("in.txt","r");
    if (NULL==f) return 1;
    while (1) {
        if (NULL==fgets(ln,100,f)) break;
        sscanf(ln,"%*s%d:00,%lf",&h[i],&d[i]);
        i++;
        if (i>=200) break;
    }
    fclose(f);
    n=i;
    for (i=0;i<n;i++) printf("%d:%d,%lg\n",i,h[i],d[i]);
    return 0;
}
//0:0,0.76
//1:12,0.87
//

[AndyStevens]

二进制数据？ fread（）

[蒙哥卡恩]

引用 1 楼 Automation_dmu 的回复:

二进制数据？ fread（）

不是二进制的主要用后边的时间和水位两组数据，弄成对应的（x，y），x是时间轴，y是水位轴，读出来后作为实参弄到一个函数里去计算拟合曲线

[derekrose]

You can use std::getline

[wb_rock]

按行读取，然后再解析

[赵4老师]

仅供参考：

#include <stdio.h>
FILE *f;
char ln[100];
int h[200];
double d[200];
int i,n;
int main() {
    f=fopen("in.txt","r");
    if (NULL==f) return 1;
    while (1) {
        if (NULL==fgets(ln,100,f)) breakl
        sscanf("%*s%d:00,%lf",&h[i],&d[i]);
        i++;
        if (i>=200) break;
    }
    fclose(f);
    n=i;
    for (i=0;i<n;i++) printf("%d:%d,%lg\n",i,h[i],d[i]);
    return 0;
}

[赵4老师]

11行 if (NULL==fgets(ln,100,f)) breakl 应改为 if (NULL==fgets(ln,100,f)) break;

[阿桑-]

我想问问 上面的程序 的{ sscanf(ln,"%*s%d:00,%lf",&h[i],&d[i]); }是不是少东西了？%s 没有对应的值，我若说错了，勿喷，

[赵4老师]

*的意思是跳过 Format Specification Fields: scanf and wscanf Functions A format specification has the following form: %

• [width] [{h | l | I64 | L}]type The format argument specifies the interpretation of the input and can contain one or more of the following: White-space characters: blank (' '); tab ('\t'); or newline ('\n'). A white-space character causes scanf to read, but not store, all consecutive white-space characters in the input up to the next non–white-space character. One white-space character in the format matches any number (including 0) and combination of white-space characters in the input. Non–white-space characters, except for the percent sign (%). A non–white-space character causes scanf to read, but not store, a matching non–white-space character. If the next character in stdin does not match, scanf terminates. Format specifications, introduced by the percent sign (%). A format specification causes scanf to read and convert characters in the input into values of a specified type. The value is assigned to an argument in the argument list. The format is read from left to right. Characters outside format specifications are expected to match the sequence of characters in stdin; the matching characters in stdin are scanned but not stored. If a character in stdin conflicts with the format specification, scanf terminates, and the character is left in stdin as if it had not been read. When the first format specification is encountered, the value of the first input field is converted according to this specification and stored in the location that is specified by the first argument. The second format specification causes the second input field to be converted and stored in the second argument, and so on through the end of the format string. An input field is defined as all characters up to the first white-space character (space, tab, or newline), or up to the first character that cannot be converted according to the format specification, or until the field width (if specified) is reached. If there are too many arguments for the given specifications, the extra arguments are evaluated but ignored. The results are unpredictable if there are not enough arguments for the format specification. Each field of the format specification is a single character or a number signifying a particular format option. The type character, which appears after the last optional format field, determines whether the input field is interpreted as a character, a string, or a number. The simplest format specification contains only the percent sign and a type character (for example, %s). If a percent sign (%) is followed by a character that has no meaning as a format-control character, that character and the following characters (up to the next percent sign) are treated as an ordinary sequence of characters, that is, a sequence of characters that must match the input. For example, to specify that a percent-sign character is to be input, use %%. An asterisk (*) following the percent sign suppresses assignment of the next input field, which is interpreted as a field of the specified type. The field is scanned but not stored.

[阿桑-]

收获了！！谢谢了！！