Question

我的问题是，如果命令行没有提供足够的参数，我希望程序改为请求所有值。出于某种原因，当我在3个参数中提供2个时，它可以工作，但是如果要提供1个或不提供任何参数，我希望它可以工作。

我的代码

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

    float areaOfcircle(float radius_circle)
    {
        float area_circle;
        area_circle = M_PI * radius_circle * radius_circle;

        return area_circle;
    }
    void resitance_current(float length, float area_circle, float voltage, float* resistance, float* current)
    {
        float resistivity;
        resistivity = 1.782*pow(10, -8);
        *resistance = ((resistivity*length) / area_circle);
        *current = (voltage / *resistance);
    }

    void radius_check(float radius)
    {
        if (radius <= 0)
        {
            printf("Radius cant be less than or equal to 0");
            exit(1);
        }
    }
    void voltage_check(float voltage)
    {

        if (voltage <= 0)
        {
            printf("Voltage cant be less than or equal to 0");
            exit(1);
        }
    }
    void length_check(float length)
    {
        if (length <= 0)
        {
            printf("Length cant be less than or equal to 0");
            exit(1);
        }
    }

    void validation(float radius, float voltage, float length)
{
    radius_check(radius);
    voltage_check(voltage);
    length_check(length);
}
    int main(int argc, char *argv[])
    {
        float radius, voltage, length, current, resistance;
        float length_u, length_l;
        //dumpargs(argc, argv);
        radius = atof(argv[1]);
        voltage = atof(argv[2]);
        length = atof(argv[3]);
        if (argc != 4)
        {
            printf("Not enough arguments supplied\n");
            printf("Enter the radius of wire : ");
            scanf("%f", &radius);
            radius_check(radius);
            printf("Enter the Voltage of circuit : ");
            scanf("%f", &voltage);
            voltage_check(voltage);
            printf("Enter the Length of Wire : ");
            scanf("%f", &length);
            length_check(length);
        }
        validation(radius, voltage, length);
        resitance_current(length, areaOfcircle(radius), voltage, &resistance, &current);
        printf("Resistance = %f , Current = %f\n", resistance, current);
        printf("\nEnter the Upper Length of Wire : ");
        scanf("%f", &length_u);
        printf("\nEnter the Lower Length of Wire : ");
        scanf("%f", &length_l);
        if ((length_l < 0) || (length_l >= length_u))
        {
            printf("\nImpossible for Lower Length < 0 or to be larger then Length Upper");
            exit(1);
        }
        else
        {
            for(length_l = length_l; length_l<=length_u; length_l++)
            {

                resitance_current(length, areaOfcircle(radius), voltage, &resistance, &current);
                printf("\nLength = %0.3f Resistance = %0.3f , Current = %0.3f", length, resistance, current);
                length = (length_l + 1);

            }
        }
        return 0;
    }

从代码“ if（argc！= 4）”中可以看出，如果通过命令行提供了值，则会再次请求并覆盖这些值。我试图对此寻求解决方案，因此，如果仅从CMD运行程序，则将请求值，但如果提供了所有值，则代码将一直运行。除了argc iss之外，代码也按要求运行。

非常感谢您提前提供帮助

Answer 1

如果传递的参数小于super.onResume()，则访问范围不受限制。

只需修改以下代码。首先检查传递的参数数量，然后访问4。

argv

还需要检查if (argc != 4) // or if (argc < 4) { printf("Not enough arguments supplied\n"); printf("Enter the radius of wire : "); scanf("%f", &radius); printf("Enter the Voltage of circuit : "); scanf("%f", &voltage); printf("Enter the Length of Wire : "); scanf("%f", &length); } else { radius = atof(argv[1]); voltage = atof(argv[2]); length = atof(argv[3]); } radius_check(radius); voltage_check(voltage); length_check(length);，Read this on how to check scanf return value的返回值。

刷新代码后出现argc位置问题

1 个答案: