为什么功能对我不起作用?C

atof函数确实效果很好。

但总的来说，您的代码中有许多严重的问题。首先，最重要的是：代码无法编译。编译器吐出许多错误。而且，它表明，出了什么问题。因此，请在使用许多错误发布代码之前运行编译器。

然后，我看到C 标签 - 查看您的标题文件。许多人最后有一个" .h"。您使用的语言C除了一行：cout << z << " " << pz << endl;。这也是错误的。它不会打印，您期望的。

您也不在此处使用任何向量。格式真的很糟糕。

让我首先进行简短的代码评论：

#include<iostream> 
#include<fstream>       // *** Not used 
#include<string>        // *** Not used 
#include<stdlib.h>      // *** Not used
#include <string.h>     // *** Not used
#include <stdio.h
#include<iomanip>       // *** Not used 
#include<cmath>         // *** Not used
using namespace std;
FILE* write, * read;    // *** Major bug. You are not using this variables, instead you are using 'leer' and 'escribir'
double dz, pm, xm, doub1, doub2;
// *** Do not use plain arrays in C++. Never
char s1[10], pz[10], s2[10], x[10], z[10]; // *** You want to be pz and z strings!
int main() {
    dz = 0.00375;
    // *** fopen is deprecated in C++
    leer = fopen("data.dat", "r");       // *** Major bug. Variable leer has not been defined
    escribir = fopen("exitdata.dat", "w+");//Donde vamos a escribir  // *** Do not write spanish// *** Major bug. Variable escribir has not been defined
    for (int a = 0; a < 5; a++) {        // *** Why 2 loops? And "a" is never used. Maybe you wan to read 5 values?
        for (int i = 0; i < 10; i++) {   // *** Why this loop? You want to copy data in the char array.
                                         // *** You are now invoking the loop body 50times
            // *** fscanf is deprecated in C++
            fscanf(read, "%s  %s n", s1, s2); // *** Read is a none initialize variabel System will crash.You opened leer
            //here begins the problem    // ** no, the problem began with trying fscanf on a none initialize file pointer
            doub1 = atof(s1);
            doub2 = atof(s2);
            z[i] = (doub1 + 1) * dz;  // Complier error. You are trying to assign a double to 1 char
            pz[i] = doub2;            // Complier error. You are trying to assign a double to 1 char
            fprintf(escribir, "%s %s n", s1, s2);
            cout << z << " " << pz << endl;   // *** Will output nothing. You are passing an empty char[]

        }
    }
    fclose(escribir);//cerrar el archivo
    fclose(leer);

    return 0;

}

对C和C 的许多错误和错误的理解。让我使代码编译。但这仍然不会做您想要的，因为您有很多语义错误。

与MS Visual Studio 2019

#include<iostream> 
#include <stdio.h>
FILE* write, *read;
double dz, pm, xm, doub1, doub2;
char s1[10], pz[10], s2[10], x[10], z[10];
int main() 
{
    dz = 0.00375;
#pragma warning(suppress : 4996)
    read = fopen("r:\data.dat", "r");
#pragma warning(suppress : 4996)
    write = fopen("r:\exitdata.dat", "w+");
    for (int a = 0; a < 5; a++) {
        for (int i = 0; i < 10; i++) {
#pragma warning(suppress : 4996)
            fscanf(read, "%s  %s n", s1, s2);
            doub1 = atof(s1);
            doub2 = atof(s2);
            //z[i] = (doub1 + 1) * dz; // No meaning
            //pz[i] = doub2;           // No meaning
            fprintf(write, "%s %s n", s1, s2);
        }
    }
    fclose(write);
    fclose(read);
    return 0;
}

当然，这也不会给您预期的结果。

，最后是代码的C 示例。请阅读一些好的C 书。请阅读有关CPPReference中使用过的功能的信息。请尝试按线路了解。

#include <iostream>
#include <fstream>
#include <vector>
#include <iterator>
#include <algorithm>
struct TwoDoubles
{
    double doub1;
    double doub2;
    // Overwrite extractor  operator
    friend std::istream& operator >> (std::istream& is, TwoDoubles& td) {
        return is >> td.doub1 >> td.doub2;
    }
    // Overwrite inserter  operator
    friend std::ostream& operator << (std::ostream& os, const TwoDoubles& td) {
        return os << td.doub1 << ' ' << td.doub2;
    }
};
int main()
{
    // Open file with source data
    std::ifstream is("r:\data.dat");
    // If file could be opened
    if (is) {
        // Open file containing results
        std::ofstream os("r:\exitdata.dat");
        // If file could be opened
        if (os)
        {
            // Define a vector of doubles and initialize it
            std::vector<TwoDoubles> values{ std::istream_iterator<TwoDoubles>(is),std::istream_iterator<TwoDoubles>() };
            constexpr double dz = 0.00375;
            // Now we will calculate. Multiply all doubles with dz;
            std::for_each(values.begin(), values.end(), [dz](TwoDoubles & td) { td.doub1 = (td.doub1 + 1) * dz; });
            // Write everything to output file
            std::copy(values.begin(), values.end(), std::ostream_iterator<TwoDoubles>(os, "n")) ;
        }
    }
    return 0;
}

请继续学习