二維數組，按總和對行排序

Question

有用戶指針的二維數組，每行填充隨機數，程序計數總和。我需要按每行的總和對數組進行排序並打印出來。例如，如果我們有數組：1 2 2（sum = 5）2 9 9（sum = 20）2 1 6（sum = 9） 輸出應該是：1 2 2（sum = 5）2 1 6 9）2 9 9（總和= 20）。感謝幫助。

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

樣本選擇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; 
} 

---

歡迎堆棧溢出選項2

的樣品

#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; 
}