c语言新手，为什么这段求平均数会输出空白

#include <stdio.h>
void main()

{
    int i;

    double average, sum=0, a[]={1.08757117,  0.68804965, -0.07223484,  0.14863247,  2.17515392,
       -1.43565082,  0.1609116 , -1.09303634, -0.27053031,  1.98091511,
        1.09970302,  0.05053113, -1.95416171,  0.35037455, -0.7413951 ,
       -0.25215941, -0.42515089,  0.74513879,  0.62237292,  1.03678863,
       -1.85304277, -0.81252199, -0.92159331, -2.40812835,  0.62350212,
       -1.28523544,  0.32784591,  0.80736635, -0.99091514, -0.82351187,
       -1.74935736,  1.61186579, -0.42659406,  0.62384358, -1.16762387,
       -0.20861519, -0.13721134,  0.05125405, -0.37726749, -0.47632967,
       -0.77551834,  1.41628295,  0.49228767, -0.24400973,  0.59446102,
        1.17769781,  0.71702727, -0.73568304, -1.58495823,  0.68823841};
        
        for (i=0; i<50; i=i++)
            scanf("%lf", &a[i]);
            for(i=0; i<50; i++)
                sum=sum+a[i];
            average=sum/50;
            printf ("average=%lf\n", average);

}

如果是求数组a中原本初始化值的平均数，去除scanf()获取输入的代码即可；

如果是重新获取输入计算输入的数的平均值，则输入50个数后，程序即会计算其平均值并打印。

修改如下：

#include <stdio.h>
int main()

{
    int i;

    double average, sum=0, a[]={1.08757117,  0.68804965, -0.07223484,  0.14863247,  2.17515392,
       -1.43565082,  0.1609116 , -1.09303634, -0.27053031,  1.98091511,
        1.09970302,  0.05053113, -1.95416171,  0.35037455, -0.7413951 ,
       -0.25215941, -0.42515089,  0.74513879,  0.62237292,  1.03678863,
       -1.85304277, -0.81252199, -0.92159331, -2.40812835,  0.62350212,
       -1.28523544,  0.32784591,  0.80736635, -0.99091514, -0.82351187,
       -1.74935736,  1.61186579, -0.42659406,  0.62384358, -1.16762387,
       -0.20861519, -0.13721134,  0.05125405, -0.37726749, -0.47632967,
       -0.77551834,  1.41628295,  0.49228767, -0.24400973,  0.59446102,
        1.17769781,  0.71702727, -0.73568304, -1.58495823,  0.68823841};
        
        for (i=0; i<50; i++){

                sum=sum+a[i];//如果是求数组原本值的平均数，去除获取输入的代码即可 
        }
        }
            
        average=sum/50;
        printf ("average=%lf\n", average);

}