动态内存分配

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

int main()
{
int numgrades, i, sum;
int *grades;

printf("\nEnter the number of grades to be processed: ");
scanf("%d", &numgrades);

/* here is where the request for memory is made */
grades = (int *) malloc(numgrades * sizeof(int));
/* here we check that the allocation was satisfied */
if (grades == (int *) NULL)
{
printf("nFailed to allocated grades array\n");
exit(1);
}

for (i = 0; i < numgrades; i++)
{
printf(" Enter a grades: ");
scanf("%d", &grades[i]);
}

printf("\nAn array was created for %d integers", numgrades);
printf("\nThe average score you entered  are:\n");

for (i = 0; i < numgrades; i++)
{
sum += grades[i];
}
printf(" %d\n", sum/numgrades);

system("pause");
free(grades);

return 0;
}