I have been studying C language for some time now, and I have a certain bug that I can't seem to be able to fix.

As part of my revision, I started coding a very simple app for stock market.

Whenever I build and run the program, the program doesn't wait for user input to enter (Y) or (N), and skips checking [If] and [else if], and instead executes [else] condition.

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

int main()
{
    int Salary;
    char key;

    printf("Enter your salary: \n");
    scanf("%d",&Salary);
    printf("Your salary = %d.\n", Salary);

    if(Salary<='10000'&&Salary>'5000')
        {
            printf("Congratulations, You are a Platinum-Tier Client!\n");
            printf("Do You want to view our specifically-tailored offers for you?\n");
            printf("Type \"Y\" for Yes, and \"N\" for No.\n\n\n");
            key=getchar();
            fflush(stdin);
            if(key=='Y')
            {
                printf("Here are our offers for you, enjoy!\n\n");
                printf("Kindly Type the number of the offer you want then press Enter.\n");
                printf("1- Real Estates.\n");
                printf("2- Stocks.\n");
                printf("3- Bonds.\n");
                printf("4- STRIPS.\n");
                printf("5- Funds.\n");
            }

            else if(key=='N')
            {
                printf("Well! Have a nice day!\n");
                printf("Kindly press Enter to exit!\n");
            }

            else
            {
                printf("Wrong choice!\n");
                printf("Type \"Y\" for Yes, and \"N\" for No.\n\n\n");
            }
        }

    else if(Salary<='5000'&&Salary>='3000')
        {
            printf("Congratulations, You are a Gold-Tier Client\n");
            printf("Do You want to view our specifically-tailored offers for you?\n");
            printf("Type \"Y\" for Yes, and \"N\" for No.\n\n\n");
            key=getchar();
            if(key=='Y')
            {
                printf("Here are our offers for you, enjoy!\n\n");
                printf("Kindly Type the number of the offer you want then press Enter.\n");
                printf("1- Real Estates.\n");
                printf("2- Stocks.\n");
                printf("3- Bonds.\n");
                printf("4- STRIPS.\n");
                printf("5- Funds.\n");
            }

            else if(key=='N')
            {
                printf("Well! Have a nice day!\n");
                printf("Kindly press Enter to exit!\n");
            }

            else
            {
                printf("Wrong choice!\n");
                printf("Type \"Y\" for Yes, and \"N\" for No.\n\n\n");
            }
        }

    else if(Salary<'3000'&&Salary>'1')
        {
            printf("Congratulations, You are a Silver-Tier Client\n");
            printf("Do You want to view our specifically-tailored offers for you?\n");
            printf("Type \"Y\" for Yes, and \"N\" for No.\n\n\n");
            key=getchar();
            if(key=='Y')
            {
                printf("Here are our offers for you, enjoy!\n\n");
                printf("Kindly Type the number of the offer you want then press Enter.\n");
                printf("1- Real Estates.\n");
                printf("2- Stocks.\n");
                printf("3- Bonds.\n");
                printf("4- STRIPS.\n");
                printf("5- Funds.\n");
            }

            else if(key=='N')
            {
                printf("Well! Have a nice day!\n");
                printf("Kindly press Enter to exit!\n");
            }

            else
            {
                printf("Wrong choice!\n");
                printf("Type \"Y\" for Yes, and \"N\" for No.\n\n\n");
            }
         }
    else
        {
           printf("Sorry! No offers for you!\n");
        }
    return 0;
}

The result is always (If I write 5000 for example):

Enter your salary:
5000
Your salary = 5000.
Congratulations, You are a Silver-Tier Client
Do You want to view our specifically-tailored offers for you?
Type "Y" for Yes, and "N" for No.


Wrong choice!
Type "Y" for Yes, and "N" for No.

What am I missing here?

Thank you for your help, and sorry if the question is kind of lame.

CodePudding user response：

You are using multibyte integer character constants as for example in this if statement

if(Salary<='10000'&&Salary>'5000')

values of which are implementation defined. Instead use integer constants like

if ( 5000 < Salary && Salary <= 10000 )

After this if statement the next if statement can be written like

else if ( 3000 <= Salary )

instead of

else if(Salary<='5000'&&Salary>='3000')

and so on for other if statements.

Using the function fflush for input stream

fflush(stdin);

has undefined behavior. Remove that statement.

This call of getchar

key=getchar();

reads the new line character '\n' stored in the input buffer after pressing the Enter key when a value of Salary was entered.

Instead use scanf the following way

scanf( " %c", &key );

Pay attention to the leading space in the format string. It allows to skip white space characters.

CodePudding user response：

So just from a quick look, try removing the ' ' from if(Salary<='10000'&&Salary>'5000') so it's if(Salary<=10000 && Salary>5000) When you surround a number with ' ' it's no longer an integer, it's an array of chars, or a string. You're comparing Salary to the ascii value of the string '5000' not the integer number 5000.