如何使用 switch 和 case 在 C [暂停] 中创建菜单

Question

I'm trying to create a menu in C that uses switch and case to navigate effectively.

I can reach the first sub menu but then it prints the top menu as well after entering a value. Also I'd need to know how to define what is being entered so I know if the teacher would like to enter the data for coursework piece 1, 2 or 3.

How would I go about doing that?

Thank you in advanced.

EDIT:

I have some basic knowledge of functions but not enough to use arrays and pointers which sounds like it'd work very well and be an elegant solution.

Here is the code in its entirety. Again, I have just started learning how to use C and apologies for any sloppy code.

int main(void)
{
    /* Function Prototypes */
int menu;
int opt1;

menu = 0;
while (menu !=4)
{
/*Display menu with 4 numbered options:*/
printf("\n     Main Menu\n");
printf("\n Type a number to enter your choice.\n");
/*1. Enter Marks*/ 
printf("\n\n1. Enter Marks\n");
/*2. Display a particular students marks*/
printf("2. Display Specific Stucdents Mark\n");
/*3. Supervisor mode*/
printf("3. Supervisor Mode\n");
/*4. Exit program*/
printf("4. Exit Program\n\n");
printf("Enter option: \n");
scanf("%d", &menu);
while (menu > 4 || menu < 1)
{
    printf("Error, please enter a valid option\n");
    scanf("%d", &menu);
}



switch (menu)
{
    case 1:
        {
        system("cls");
        printf("1. Enter Marks\n");
        printf("2. Return to menu\n");
        scanf("%d", &opt1);
        if (opt1 = 1)
        switch (opt1)
        {
            case 1:
                {
                    printf("Is the mark for coursework 1, 2 or 3?");
                }
        }
        /*Are the marks for course work 1, 2 or 3?*/
        /*Enter Marks*/
        /*Display results table*/
        /*Option to edit*/
        /*Confirm and return to menu*/
        }

Answer 1

A list of a few things where you are wrong:

scanf("%d", &j);

You must test the return value of scanf . It will tell you whether it read a valid number.

printf("Please enter the number of students...);
scanf("%d", &j);  // so j holds the number of students
...
name=(char*)calloc(j, sizeof(char));

You just allocated j characters . I don't think that is what you want. What do you want anyway?

    scanf("%s",&name[i]);

What is this? You try to read a string into a single character? Again, what do you want? If you want to read all the names of the students, you should have started with allocating an array of strings and memory for each string, such as:

char **name= malloc(j*sizeof(char *));
for (int i= 0; i<j; i++) {
    name[i]= malloc(80); // allocate 80 charrs for each name
    printf("Enter name for student %d:\n", i+1);
    scanf("%80s", name[i]);
}

You should have your menu in a loop:

do {
    printmenu();
    menu= 0;
    if (scanf("%d", &menu)==1) {
        switch (menu) {
            case 1: ....; break;
            case....
            default:...
       }
    }
} while (menu !=0);

Note that if (opt1 = 1) will assigne 1 to opt1 . I think you mean if (opt1==1)

So far; the rest is for you.

(Note: in the interest of learning, i did not provide an advanced solution; just the basics.)