c - 我想使用指针从函数返回多个值，但它返回一个值

Question

我想从用户定义函数返回多个值，但它只返回一个变量。这是代码:

#include <stdio.h>
double sum_n_avg(double, double, double, double*, double*);

int main()
{
    double n1, n2, n3, sump, avgp;
    printf("enter numbers:");
    scanf("%lf%lf%lf", &n1, &n2, &n3);

    printf("sum and average is %lf",sum_n_avg(n1, n2, n3, &sump, &avgp));
    return 0;
}

double sum_n_avg(double n1, double n2, double n3, double *sump, double *avgp)
{
    *sump = n1 + n2 + n3;
    *avgp = *sump / 3;

}

Answer 1

您的代码具有未定义的行为，如 sum_n_avg() 不返回任何内容，但 printf("sum and average is %lf", ??); 期望一个值.

但你期待这样的事情

void sum_n_avg(double n1,double n2,double n3,double *sump,double *avgp) {
        *sump=n1+n2+n3;
        *avgp=*sump/3;         
}
int main() {
        double n1,n2,n3,sump,avgp;
        printf("enter numbers:");
        scanf("%lf%lf%lf",&n1,&n2,&n3);

        sum_n_avg(n1,n2,n3, &sump,&avgp); /* call like this */
        printf("sum and average is %lf and %lf\n",sump,avgp);/*sump and avgp gets updated from sum_n_avg() function */
        return 0;
}