Need help with menu control 'C'

Aug 18, 2020 at 10:37am
Mif (403)
How to avoid terminating the program if someone type 0 (zero)?

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#include <stdio.h>
#include <windows.h>

unsigned temp, status, options;

void add_sub();
void mult_dev();
void increm_decrem();
void average();

void menu()
{
    printf("\n\t\t\t    * Calculator *\n\n");
    printf("\n\tChoose an option"
           "\n\n\n 1. Addition and subtraction operations"
           "\n 2. Multiply and divide operations"
           "\n 3. Increment and Decrement operations"
           "\n 4. Average of n numbers using arrays"
           "\n 5. Exit program"
           "\n\n Select: ");
    status = scanf("%d", &options);
    while(status != 1)
    {
        while((temp = getchar()) != EOF && temp != '\n')
        {
            printf("\n\n Invalid option..");
            Sleep(1500);
            printf("\n\n Choose 1, 2, 3, 4 or 5\n");
            Sleep(1500);
            system("cls");
            printf("\n\t\t\t    * Calculator *\n\n");
            printf("\n\tChoose an option"
                   "\n\n\n 1. Addition and subtraction operations"
                   "\n 2. Multiply and divide operations"
                   "\n 3. Increment and Decrement operations"
                   "\n 4. Average of n numbers using arrays"
                   "\n 5. Exit program"
                   "\n\n Select: ");
            status = scanf("%d", &options);
        }
    }
}

int main()
{
    menu();
    int i;
    for(i = 0; i < options;)
    {
        if(options == 1)
        {
            printf("\n\n\t 1. Addition and subtraction operations");
            add_sub();
        }
        else if(options == 2)
        {
            printf("\n\n\t 2. Multiply and divide operations");
            mult_dev();
        }
        else if(options == 3)
        {
            printf("\n\n\t 3. Increment and Decrement operations");
            increm_decrem();
        }
        else if(options == 4)
        {
            printf("\n\n\t 4. Average of n numbers using arrays");
            average();
        }
        else if(options == 5)
        {
            printf("\n\n\t 5. Exit program");
            printf("\n\n\t\tPress any key to close the console !");
            Sleep(1500);
            system("cls");
            break;
        }
        else
        {
            printf("\n\n Invalid option..");
            Sleep(1500);
            printf("\n\n Choose 1, 2, 3, 4 or 5\n");
            Sleep(1500);
            system("cls");
            menu();
        }
    }
    return 0;
}
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Edit & run on cpp.sh


If anything else is type the program run correctly and does what I have write to do, but pressing 0(zero) the program terminates.
How to avoid that ?
Aug 18, 2020 at 10:57am
Mif (403)
Ok.. got it.. while I was checking the code I found this..

 
 
 while((temp = getchar()) != EOF && temp != '\n')


I had to change temp != '\0' the escape sequences instead of '\n'.

Ty everyone..
Last edited on Aug 18, 2020 at 10:57am
Aug 18, 2020 at 11:34am
salem c (3715)
> while((temp = getchar()) != EOF && temp != '\n')
Given that EOF is guaranteed to be a negative, having temp as an unsigned is going to lead to surprises at some point.

Also, try to return results rather than relying on global variables.
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