Thread: Explain this IF statement, please.

Please take a look at this code:

Code:

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

//Tells computer when ARRAY_SIZE is used to automate 100
#define ARRAY_SIZE 30



int main(void){

    //int grade[ARRAY_SIZE];
    int *grade;
    char continueResponse; //Y/N
    int count = 0;
    int i; //loop conditional variable


//allocates memory for the data
grade =malloc(sizeof(int) * ARRAY_SIZE);
if(grade == 0){
    exit(1); //return 1;
}

printf("This program will create a list of your grades.\nPress ENTER after each grade.\n\n");

//input loop
for(i = 0; i < ARRAY_SIZE; i++)
    {
    printf("Enter grade percentage(0-100) [%02d/%02d]: ", i+1, ARRAY_SIZE);
    scanf("%d",&grade[i]); //caps the inputs to array size of 30
    count++; //count=count + 1; increments to next position in array
    printf("Continue? (Y/N): ");
    scanf(" %c",&continueResponse);//reads response

    if(continueResponse != 'Y' &&continueResponse != 'y')
        {
        printf("\n == Grade Book ==\n\n");
        break;//break out of for loop
        }
    }

printf("Grades entered: \n");

for(i = 0; i < count; i++){
    printf("\t%d\n", grade[i]);
}
free(grade);

return 0;
}

What is this section doing? How/why is the "1" variable there?

Code:

if(grade == 0){
    exit(1); //return 1;