该程序是要求输入一个电源电压和两个电阻值，把他们写入curres文本，然后读取他们，进行电流和功率的计算。I=U/(R1+R2),P=I^2*R.然后在新的文本powcur上列出结果。我写的这个程序，在输入电压和电阻之后，电脑进行了计算，电流的结果也出现在了curres文本里，但是为何程序就不再进行下去了？请前辈们帮忙看一下。。。

原题：Given is a circuit with two resistors  (R1 and R2) in series, connected to a voltage source (U).  
    U and R1 are being entered and then a number of values for R2 are being entered. While entering the value(s)
    for  R2 the current  I flowing through it is calculated.
    Write a program that for each value of R2 being entered writes this value and the current I to a textfile
    (to stop the program, enter 0 for R2).  
Next, write a program that reads this textfile and calculates for each pair (I,R2) the power P = I2R.  
The triplet (I,R2,P) is to be written to a new textfile.
    After all values are written, the content of this new file is to be ptited to the screen.


我写的如下：

#include <stdio.h>
#include <math.h>
#include <stdlib.h>

void main()
{   
    FILE *fout,*fin;
        float R1,R2,I,P1,P2;
        float U,P;
    float fRes, fCur;

    fout = fopen("curres.txt", "w");
    printf("Please enter U and R1: ");
    scanf("%f %f", &U,&R1);

    while(U < 0.00f || R1 < 0.00f)
    {
        printf("Invalid!\nPlease enter U and R1: ");
        scanf("%f %f", &U,&R1);
    }

    printf("Please enter  R2:\n");
    while(1)
    {
        scanf("%f", &R2);
        if(!R2)break;
        if(R2 < 0.00f)
            printf("Invalid!\n");
        else
            fprintf(fout,"%f %f\n",R2, U/(R1+R2));
    }
 
    fin = fopen("curres.txt", "r");
    if (fin == NULL)
    {
        printf("ERROR: the file is not opened!\n");
        exit (0);
    }

   
    fout = fopen("powcur.txt", "w");
    if (fout == NULL)
    {
        printf("ERROR: the file is not opened!\n");
        exit (0);
    }

    while(fscanf(fin,"%f%f",&fRes, &fCur) != EOF)
    {
        float fPow = fCur*fCur*fRes;
        printf("%f*%f*%f = %f\n",fCur, fCur, fRes, fPow);
        fprintf(fout,"%f %f %f\n", fRes, fCur, fPow);
    }
        fclose(fin);
    fclose(fout);

    printf("Press any key to continue. . .\n");
    getch();

    return 0;
}

在fin = fopen("curres.txt", "r");之前

加上

fclose(fout);


测试通过的代码

#include <stdio.h>
#include <math.h>
#include <stdlib.h>

void main()
{
    FILE *fout,*fin;
        float R1,R2,I,P1,P2;
        float U,P;
    float fRes, fCur;

    fout = fopen("curres.txt", "w");
    printf("Please enter U and R1: ");
    scanf("%f %f", &U,&R1);

    while(U < 0.00f || R1 < 0.00f)
    {
        printf("Invalid!\nPlease enter U and R1: ");
        scanf("%f %f", &U,&R1);
    }

    printf("Please enter  R2:\n");
    while(1)
    {
        scanf("%f", &R2);
        if(!R2)break;
        if(R2 < 0.00f)
            printf("Invalid!\n");
        else
            fprintf(fout,"%f %f\n",R2, U/(R1+R2));
    }
    fclose(fout);

    fin = fopen("curres.txt", "r");
    if (fin == NULL)
    {
        printf("ERROR: the file is not opened!\n");
        exit (0);
    }


    fout = fopen("powcur.txt", "w");
    if (fout == NULL)
    {
        printf("ERROR: the file is not opened!\n");
        exit (0);
    }

    while(fscanf(fin,"%f%f",&fRes, &fCur) != EOF)
    {
        float fPow = fCur*fCur*fRes;
        printf("%f*%f*%f = %f\n",fCur, fCur, fRes, fPow);
        fprintf(fout,"%f %f %f\n", fRes, fCur, fPow);
    }
        fclose(fin);
    fclose(fout);

    printf("Press any key to continue. . .\n");
    getch();

    return 0;
}

谢谢您的回复，我试过了，依然是那样的情况，我在输入完U和R1,R2之后，按回车键，依然没有关闭curres.txt,就停在这里不动了。

LZ的程序主要是输入R2时的循环用错了，还有第一次文件打开后没有关闭。以下是修改后的程序：

#include <stdio.h>

int main(void)
{   
    FILE *fout,*fin;
    float R1,R2,I,P1,P2;
    float U,P;
    float fRes, fCur;

    fout = fopen("curres.txt", "w");

    printf("Please enter U and R1: ");
    scanf("%f%f", &U,&R1);

    while(U < 0.00f || R1 < 0.00f)
    {
        printf("Invalid!\nPlease enter U and R1: ");
        scanf("%f %f", &U,&R1);
    }

    printf("Please enter  R2: ");
    scanf("%f", &R2);

    if(R2 < 0.00f)
        printf("Invalid!\n");
    else
        fprintf(fout,"%f\n%f\n",R2, U/(R1+R2));
    fclose(fout);/* 注意 */

    fin = fopen("curres.txt", "r");

    if (fin == NULL)
    {
        printf("ERROR: the file is not opened!\n");
        exit (0);
    }

    
    fout = fopen("powcur.txt", "w");

    if (fout == NULL)
    {
        printf("ERROR: the file is not opened!\n");
        exit (0);
    }

    while(fscanf(fin,"%f\n%f\n",&fRes, &fCur) != EOF)
    {
        float fPow = fCur*fCur*fRes;
        printf("\n%f*%f*%f = %f\n",fCur, fCur, fRes, fPow);
        fprintf(fout,"%f\n%f\n%f\n", fRes, fCur, fPow);
    }
    fclose(fin);
    fclose(fout);
    printf("\nPress any key to continue...");
    getch();
    return 0;
} 

你的问题描述说的很清楚了

Write a program that for each value of R2 being entered writes this value and the current I to a textfile
    (to stop the program, enter 0 for R2).

并不是停在那里不动了,而是等待下一次输入,一直不停的输入R2,直到R2为0,程序结束,R2是指内的各个电阻