下面程序在排序后计算每一行的总和和平均值，为什么程序运算不出来？请问是什么原因？

#include "stdio.h"
int main()
{
unsigned int i,j,z,t;
unsigned int m[2][4];
printf("input 8 numbers:\n");
for (i=0; i<2; i++)
for (j=0; j<4; j++)
scanf ("%u", &m[i][j]);
for (i=0; i<2; i++)
{
for (j=0; j<4; j++)
printf("%5u",m[i][j]);
printf("\n");
}
for (z=0; z<2; z++)
for (i=0; i<4-1; i++)
for(j=0; j<4-1-i; j++)
if (m[z][j]>m[z][j+1])
{
int t=m[z][j];
m[z][j]=m[z][j+1];
m[z][j+1]=t;
}
printf("Sort results:\n");
for (j=0; j<2; j++)
{
for (z=0; z<4; z++)
printf("%5u", m[j][z]);
printf("\n");
}
return 0;
int sum[i];
for(i=0;i<2;i++)
{
sum[i]=0;
printf("%5u",i+1);
for(j=1;j<3;j++)
{
scanf("%d",&m[i][j]);
sum[i]=sum[i]+m[i][j];
}
}
printf("\n%10s%10s%10s\n","Code""Sum""Average") ;
for(i=0;i<2;i++)
for(j=1;j<3;j++)
{
printf("%10d%10d%10.2f\n",i+1,sum[i],sum[i]/2.0);
}
}

#include "stdio.h"
int main()
{
    unsigned int i, j, z, t;
    unsigned int m[2][4];
    printf("input 8 numbers:\n");
    for (i = 0; i < 2; i++)
        for (j = 0; j < 4; j++)
            scanf("%u", &m[i][j]);
    for (i = 0; i < 2; i++)
    {
        for (j = 0; j < 4; j++)
            printf("%5u", m[i][j]);
        printf("\n");
    }
    for (z = 0; z < 2; z++)
        for (i = 0; i < 4 - 1; i++)
            for (j = 0; j < 4 - 1 - i; j++)
                if (m[z][j] > m[z][j + 1])
                {
                    int t = m[z][j];
                    m[z][j] = m[z][j + 1];
                    m[z][j + 1] = t;
                }
    printf("Sort results:\n");
    for (j = 0; j < 2; j++)
    {
        for (z = 0; z < 4; z++)
            printf("%5u", m[j][z]);
        printf("\n");
    }
    int sum[1024];
    for (i = 0; i < 2; i++)
    {
        sum[i] = m[i][0];
        printf("%5u", i + 1);
        for (j = 1; j <= 3; j++)
        {
            //scanf("%d", &m[i][j]);
            sum[i] = sum[i] + m[i][j];
        }
    }
    printf("\n%10s%10s%10s\n", "Code","Sum","Average");
    for (i = 0; i < 2; i++)
        printf("%10d%10d%10.2f\n", i + 1, sum[i], sum[i] / 4.0);
    return 0;
}

32行直接返回了，后面的程序就不会运行了