I am not able to execute a program which includes user input of a integer inside an else if statement

/when user enters 1,2 or 3, the program exits without scanning for the quantities inside the else if statements block how to scan inside a if or else if statment/

if (num==4)
{
    printf("exiting");
    goto end;
}

else
{
    if (num=='1')
    {
        printf("enter the value of the first unit\n");
        scanf("%f",&first);
        second=first*kmstomiles;
        printf("the value of the second unit is %f",second);
    }  

     else if (num=='2')
    {
         printf("enter the value of the first unit\n");
        scanf("%f",&first);
        second=first*inchestofeet;
        printf("the value of the second unit is %f",second);

    }
    else if (num=='3')
    {
        printf("enter the value of the first unit\n");
        scanf("%f",&first);
        second=first*cmtoinches;
        printf("the value of the second unit is %f",second);
    }