From https://www.facebook.com/groups/ubuntu.zh.hant/permalink/571374706251189/

hw1.c

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

int main(int argc, char* argv[]){
  int row=0, col=0;
  int i=0,j=0;
  int m=0,n=0;
  int tmp=0,sum=0;
  float avg=0;
  FILE* input=fopen("2d_ary.txt","r");
  int **num=(int**)calloc(row,sizeof(int*));
  int* vs=(int*)calloc(row,sizeof(int));
  fscanf(input," %d %d", &row,&col);
  // printf("%d, %d\n", row, col);
  for(i=0;i<row;i++){
    num[i]=(int*)calloc(col,sizeof(int));
    for(j=0;j<col;j++){
      fscanf(input,"%d", (num[i]+j));
    }
  }
  /* for(i=0;i<row;i++){
    for(j=0;j<col;j++){
      printf("%d ", *(num[i]+j));
    }
    printf("\n");
  }*/
  for(i=0;i<col;i++){
    for(j=0;j<row;j++){
      vs[j]=*(num[j]+i);
    }
    for(m=0;m<row;m++){
      for(n=row-1;n>m;n--){
        if(vs[n]<vs[n-1]){
          tmp=vs[n-1];
          vs[n-1]=vs[n];
          vs[n]=tmp;
        }
      }
    }
    sum=0;
    avg=0;
    for(m=0;m<row;m++)
      sum+=vs[m];
    avg=(float)sum/row;
    printf("column %d: minimum=%d, maximum=%d, average=%.4f\n", i+1, vs[0], vs[row-1], avg);
  }
  return 0;
}