2D array, sort rows by sum - c

Question

There is 2D array with pointers from user, filled with random numbers, program count sum of every row. I need to sort array by sum of every row and print it. For example if we have array:1 2 2 (sum=5)2 9 9 (sum=20)2 1 6 (sum=9)
output should be:1 2 2 (sum=5)2 1 6 (sum=9)2 9 9 (sum=20). Thanks for help.
int main () {
int i, j, row, column, **array,sum;
time_t seconds;
time (&seconds);
srand ((unsigned int)seconds );
printf ("Write number of rows:");
scanf ("%d", &row);
printf ("Write number of columns:");
scanf ("%d", &column);
array=(int**) malloc (row * sizeof(int *));
if (array!=NULL){
for (i=0; i<row;i++)
array[i]= (int*) malloc (column *sizeof(int));
}
for (i=0; i<row;i++)
for (j=0; j<column;j++)
array[i][j]=(rand()%100);
for (i=0; i<row;i++){
for (j=0; j<column;j++)
printf("%d ",array[i][j] );
printf ("\n");
}
for(i=0;i<row;i++){ //find sum of each row
sum=0;
for(j=0;j<column;j++){
sum=sum+array[i][j];
}
printf("%d \n",sum);
}
return 0;
}

Answer 1

sample of option 1
#include <stdio.h>
#include <stdlib.h>
int COLUMNS;
int sum(int len, int *array){
int i, sum = 0;
for(i=0; i<len; ++i)
sum += *array++;
return sum;
}
int cmp(const void *a, const void *b){
int sum1 = sum(COLUMNS, *(int**)a);
int sum2 = sum(COLUMNS, *(int**)b);
return (sum1 > sum2) - (sum1 < sum2);
}
int main(void){
int i, j, row, column, **array;
row = 3; column = 3;
array = (int**) malloc (row * sizeof(*array));//cast of (int**) is redundant.
array[0] = (int []){1, 2, 2};
array[1] = (int []){2, 9, 9};
array[2] = (int []){2, 1, 6};
COLUMNS = column;//size of columns pass to compare function by global variable.
qsort(array, row, sizeof(*array), cmp);
for (i=0; i<row;i++){
for (j=0; j<column;j++)
printf("%d ",array[i][j] );
printf ("\n");
}
free(array);
return 0;
}
sample of option 2
#include <stdio.h>
#include <stdlib.h>
int sum(int len, int *array){
int i, sum = 0;
for(i=0; i<len; ++i)
sum += *array++;
return sum;
}
typedef struct pair {
int *p;//or index
int sum;
} Pair;
int cmp(const void *a, const void *b){
Pair const *x = a;
Pair const *y = b;
return (x->sum > y->sum) - (x->sum < y->sum);
}
int main(void){
int i, j, row, column, **array;
row = 3; column = 3;
array = (int**) malloc (row * sizeof(*array));//cast of (int**) is redundant.
array[0] = (int []){1, 2, 2};
array[1] = (int []){2, 9, 9};
array[2] = (int []){2, 1, 6};
Pair *temp = malloc(row * sizeof(*temp));
for(i = 0; i < row; ++i){
temp[i].p = array[i];
temp[i].sum = sum(column, array[i]);
}
qsort(temp, row, sizeof(*temp), cmp);
for (i=0; i<row;i++){
for (j=0; j<column;j++)
printf("%d ", temp[i].p[j] );
printf ("\n");
}
free(temp);
free(array);
return 0;
}