二维数组打印方式错误

Question

I'm creating a 2D dynamic array to keep track of transactions over several days. I have created the 2D array and added the transactions. The problem is that is not printing the correct transactions. It will print correctly if I have the same amount of noOfdays and transcount. Ex 3 and 2. But it changes values if I have noOfdays 2 and trascount 3.

Example output having noOfdays 2 and trascount 3.

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

int main(int argc, char const *argv[]) {

int noOfDays, transcount;
printf("Enter no of days:");
scanf("%d", &noOfDays);
printf("Enter total no of transaction:\n ");
scanf("%d", &transcount);
int *p= (int)malloc(noOfDays*transcount * sizeof(int));

int number = 0;
for (int i = 0; i < noOfDays; i++) {
  printf("Enter no of transaction per day:\n", i);
for (int j = 0; j < transcount; j++) {
  scanf("%d", &number);
  p[i*noOfDays + j] = number;
 }

}

printf("%s\n", "#Printing your 2d array:" );
for (int i = 0; i < noOfDays; i++){
 for (int j = 0; j < transcount; j++){
  int number = p[i*noOfDays + j];
  printf("%d\t", number);
}
printf("\n");
}

return 0;
}

Answer 1

It's probably your index formula in p[i*noOfDays+j] is not correct.

Change it from p[i*noOfDays+j] to p[i*transcount+j] .

The reason is the i is the index of the current transaction group. The j is the index of specific transaction in a day.