c - 运行程序返回 -1.#QNAN0

Question

在使用输入文件计算总和时，该文件包含两列数字以及第一列上方的整数导向器，当我创建第二列数字的总和时，我遇到了一个错误, conductivity, 它不是一个数字，并且返回-1.#QNAN0，我试过更改变量名和更改顺序，我知道这与这个问题无关。另外，当我运行程序时，屏幕上显示了电导率值，但由于某种原因无法汇总。

/* Main Function */
int main(void) {
    /* Declare and initialize Variables */
    double temp, conduc, tempsqrd, temptconduc, sumtemp, sumconduc;
    double sumtempsqrd, sumtemptconduc, slope, yint;
    int i, ndata;
    FILE *therm, *out;

    /* Open Files */
    therm = fopen(inputfile, "r");
    out = fopen(outputfile, "w");

    /* print output headings */
    printf("******************************************");
    printf("\n   TEMPERATURE vs THERMAL CONDUCTIVITY"
           "\n           by Tyrus Sonneborn"
           "\n\nTemp    Conduct    Temp Sqrd    Temp*Conduct");
    fprintf(out, "******************************************");
    fprintf(out, "\n    TEMPERATURE vs THERMAL CONDUCTIVITY"
                 "\n           by Tyrus Sonneborn"
                 "\n\nTemp    Conduct    Temp Sqrd    Temp*Conduct");   

    /* Verify input file and read control number */
    if (therm == NULL) {
        printf("\n\n\n\n   ERROR OPENING INPUT FILE.");
        printf("\n\n   PROGRAM TERMINATED.\n\n\n");
        return 0;
    } else {
        /* Read control number */
        fscanf(therm, "%i", &ndata);

        /* Compute the conductivity data and sums. */
        for (i = 1; i <= ndata; i++) {
            fscanf(therm, "%lf %lf", &temp, &conduc);
            sumconduc = conduc + sumconduc;
            tempsqrd = pow(temp, 2);
            temptconduc = temp * conduc;
            sumtemp = temp + sumtemp;
            sumtempsqrd = sumtempsqrd;
            sumtemptconduc = sumtemptconduc;
            printf("\n %3f     %4.0f       %6.0f       %6.0f",
                   temp, conduc, tempsqrd, temptconduc);
            fprintf(out, "\n %3f     %5.1f       %6.0f      %6.0f",
                    temp, conduc, tempsqrd, temptconduc);
        }
    }
    /* computing the slope and y intercept */
    slope = (sumtemp * sumconduc - ndata * sumtemptconduc) / (pow(sumtemp, 2) - ndata * (pow(sumtemp, 2)));
    yint = (sumconduc - slope * sumtemp) / ndata;
    printf("\n\n%10f, %10f, %10f, %10f",
           sumtemp, sumconduc, sumtempsqrd, sumtemptconduc);
    fprintf(out, "\n\n%10f, %10f, %10f, %10f",
            sumtemp, sumconduc, sumtempsqrd, sumtemptconduc);

Answer 1

在for循环中，你使用未初始化的sumconduc:

sumconduc = conduc + sumconduc;

您应该将其初始化为0。 sumtemp、sumtempsqrd 和 sumtempconduc 也是如此。

通过 gcc -Wall -Wextra 启用警告进行编译会诊断出此类愚蠢的错误。