How can I debug this basic IF-ELSE program?

Question

I'm new to coding C.

I wrote a basic program for calculating interest (the method of calculating simple interests is incorrect, but this is not the place where the current problem lies). I am inserting the code here so you can better understand the problem.

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

int main()
{
    printf("This is a program which calculates your balance each year for 5 years! \n");

    char name [30];
    float principal;
    float interestRate;
    int interestType;
    int age;

    printf("Start by entering your name \n");
    scanf("%s", name);

    printf("Please enter the type of interest you earn (Simple = 1, Compound = 2) \n");
    scanf("%d", interestType);

    if (interestType == 1)
    {
        printf("You have chosen your interest type as simple \n");

        printf("Please enter your age \n");
        scanf(" %d", &age);

        // IF statement
        if (age < 18)
        {
            printf("You're not eligible for a bank account yet");
        }
        // ELSEIF statement
        else if (age > 122)
        {
            printf("Please submit your age to the Guinness Book of World Records and try again");
        }
        //ELSE statement
        else
        {
            printf("Please enter your current account balance \n");
            scanf(" %f", &principal);

            //Nested IF statement
            if (principal == 0)
            {
                printf("You don't have any balance, please fill money in your account and try again \n");
            }
            else
            {
                printf("Please enter the rate of interest at which your money is being multiplied \n");
                scanf(" %f", &interestRate);

                // principal *= interestRate is the same as principal = principal * interestRate
                principal = principal + interestRate;
                printf("%s balance after 1 year will be %f \n", name, principal);

                principal = principal + interestRate;
                printf("%s balance after 2 years will be %f \n", name, principal);

                principal = principal + interestRate;
                printf("%s balance after 3 years will be %f \n", name, principal);

                principal = principal + interestRate;
                printf("%s balance after 4 years will be %f \n", name, principal);

                principal = principal + interestRate;
                printf("%s balance after 5 years will be %f \n", name, principal);

                printf("Thats all");
            }
        }
    }

    else if (interestType == 2)
    {
        printf("You have chosen your interest type as compound \n");

        printf("Please enter your age \n");
        scanf(" %d", &age);

        // IF statement
        if (age < 18)
        {
            printf("You're not eligible for a bank account yet");
        }
        // ELSEIF statement
        else if (age > 122)
        {
            printf("Please submit your age to the Guinness Book of World Records and try again");
        }
        //ELSE statement
        else
        {
            printf("Please enter your current account balance \n");
            scanf(" %f", &principal);

            //Nested IF statement
            if (principal == 0)
            {
                printf("You don't have any balance, please fill money in your account and try again \n");
            }
            else
            {
                printf("Please enter the rate of interest at which your money is being multiplied \n");
                scanf(" %f", &interestRate);

                // principal *= interestRate is the same as principal = principal * interestRate
                principal *= interestRate;
                printf("%s balance after 1 year will be %f \n", name, principal);

                principal *= interestRate;
                printf("%s balance after 2 years will be %f \n", name, principal);

                principal *= interestRate;
                printf("%s balance after 3 years will be %f \n", name, principal);

                principal *= interestRate;
                printf("%s balance after 4 years will be %f \n", name, principal);

                principal *= interestRate;
                printf("%s balance after 5 years will be %f \n", name, principal);

                printf("Thats all");
            }
        }
    }

    return 0;
}

The problem I am facing is that whenever a program starts up and asks for the type of interest, after entering the input number (1 or 0) it just stops.

Answer 1

, "&". scanf("%d", interestType);. scanf("%d", &interestType);. 1 2. else . .

Answer 2

scanf("%s", name);, &: scanf("%s", &name);

, gets();, . , .