[英]Reading Scientific Notation in C
I am trying to read a file that has the following contents: 我正在尝试读取具有以下内容的文件:
1.0000000e+01 2.9265380e+03 5.0821200e+02 4.3231640e+01
1.0000000e + 01 2.9265380e + 03 5.0821200e + 02 4.3231640e + 01
2.0000000e+01 1.0170240e+04 9.2798610e+02 4.0723180e+01
2.0000000e + 01 1.0170240e + 04 9.2798610e + 02 4.0723180e + 01
3.0000000e+01 2.1486260e+04 1.1832420e+03 1.0328000e+01
3.0000000e + 01 2.1486260e + 04 1.1832420e + 03 1.0328000e + 01
4.0000000e+01 3.3835080e+04 1.1882285e+03 -9.3307000e+00
4.0000000e + 01 3.3835080e + 04 1.1882285e + 03 -9.3307000e + 00
5.0000000e+01 4.5250830e+04 1.0899705e+03 -1.0320900e+01
5.0000000e + 01 4.5250830e + 04 1.0899705e + 03 -1.0320900e + 01
6.0000000e+01 5.5634490e+04 9.8935650e+02 -9.8019000e+00
6.0000000e + 01 5.5634490e + 04 9.8935650e + 02 -9.8019000e + 00
7.0000000e+01 6.5037960e+04 8.9134700e+02 -9.8000000e+00
7.0000000e + 01 6.5037960e + 04 8.9134700e + 02 -9.8000000e + 00
but I can't seem to find a proper way to read the scientific notation. 但我似乎无法找到一种阅读科学记谱法的正确方法。 Here is what I have of the code:
这是我的代码:
#include <stdio.h>
#include <stdlib.h>
int main()
{
// This is the array to store the input
double time[24], altitude[24], velocity[24], acceleration[24];
double var1, var2, var3, var4;
//This is the pointer declaration for opening a file
FILE * fp = fopen("rocket.txt", "r");
int i = 0;
while(fscanf(fp,"%g %f %f %f", &var1, &var2, &var3, &var4) > 0){
time[i] = var1;
altitude[i] = var2;
velocity[i] = var3;
acceleration[i] = var4;
printf("Time: %f \n", &time[i]);
i++;
}
printf("Time: %f", &time[0]);
fclose(fp);
return(0);
}
I've tried multiple combinations of %f, %g, %d
to try and print out the result but I can never get the right thing. 我已经尝试了
%f, %g, %d
多种组合来尝试打印出结果,但我永远无法得到正确的结果。
If anyone can point me on the right direction I will greatly appreciate it. 如果有人能指出我正确的方向,我将非常感激。
What you want to use is %lf
for input and %e
for output in scientific notation: 您想要使用的是输入的
%lf
和科学计数法输出的%e
:
scanf("%lf", &input);
printf("%e\n", input);
You could use a, e, f, or g in the conversion specifier like this: 您可以在转换说明符中使用a,e,f或g,如下所示:
fscanf(fp, "%a", &input); // NOTE: only with C99 compilers
fscanf(fp, "%e", &input);
fscanf(fp, "%f", &input);
fscanf(fp, "%g", &input);
They will all work for parsing floats, but for doubles you will need to use the length modifier "l" like this: 它们都可用于解析浮点数,但对于双精度数,你需要使用长度修饰符“l”,如下所示:
fscanf(fp, "%le", &input);
To print the values, you can use any of the specifiers but you don't need the length modifier "l": 要打印值,可以使用任何说明符,但不需要长度修饰符“l”:
printf("%e ", input); // or f or g (or a C99 compilers only)
printf("%le ", input); // produces the same thing
A really helpful reference is here: http://en.cppreference.com/w/c/io/fscanf 这里有一个非常有用的参考: http : //en.cppreference.com/w/c/io/fscanf
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