C program , variable is automatically becoming zero after character input

here in this program num1 value is changing into zero inside if- else condition. i am getting wrong answer as the variable is automatically becoming 0. why is that? if i give num1 as 4 and num2 as 3. i am getting added value as 3, it should be 7 right. kindly help to solve

#include<stdio.h>
void main()
{
    int num1, num2, answer;
    char type;

    printf("Enter num1\n");
    scanf("%d",&num1);
    printf("Enter num2\n");
    scanf("%d",&num2);
    printf("type a for addition or s for subtraction\n");
    scanf("%s",&type);

    if(type == 'a')
    {
        answer = num1 + num2;
        printf("answer is %d \n",add);
    }
    else if(type == 's')
    {
        answer = num1 - num2;
        printf("answer is %d \n",sub);
    }
    else
    {
        printf("enter a or s");
    }
}