How to write a console menu in ANSI/ISO C? - c

Question

I'm trying to create a simple program in c, where the user has to choose between several options:
char command = '1';
while(command!='0') {
printf("Menu:\n");
printf("1. First option\n");
printf("2. Second option\n");
printf("0. Exit\n");
printf("Choose: 0,1,2?: ");
command = getchar();
while(getchar()!='\n');
switch(command) {
case '0': break;
case '1': functionCall1(); break;
case '2': functionCall2(); break;
}
}
The problem with my code is, that every second time I enter 1,2 or 0, nothing happens, only the menu prints itself again. With the debugger I can see, that the value of command, after command = getchar() equals '', every second time. I thought that eating the newline character is enough?

Answer 1

Try my customized menu, I implemented it to make my life easier when I work with programs which contains multiple choices operations.
Menu is navigable (arrows:up, down, left, right), and for making a selection you only need to press enter key, menu orientation can be set vertically or horizontally, padding can be set to a group of items(childrens), child starting position, and update with delay.
Menu call example (vertically):
int response = menu("OPTIONS","[*]","->",
1,3,3,0,5,
"PROFILES","ACTIVITY","VIDEO","SOUND","GAMEPLAY");
The most important thing is because function implementation takes only 60 lines of code.
Menu implementation:
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <windows.h>
// LXSoft
// mod: cui/menu_021
// stdarg.h -> used for variable list of arguments (va_list, va_start ...)
// windows.h -> used for Sleep function, for *nix use unistd.h
typedef unsigned short int usint_t;
// Menu function prototype
int menu(char* name, char* prefix, char* cursor, usint_t orientation,
usint_t padding, usint_t start_pos, usint_t delay,
usint_t num_childs, ...);
int main()
{
int response = menu("OPTIONS","[*]","->",1,3,3,0,5,
"PROFILES","ACTIVITY","VIDEO","SOUND","GAMEPLAY");
switch(response)
{
case 1:
// doSomethingFoo1();
break;
case 2:
//doSomethingFoo2();
break;
/*
* .
* .
* .
* case n:
* break;
*/
}
printf("\nYour choice is: %d", response);
return 0;
}
// Menu implementation
int menu
(
char *name, // Menu name (eg.: OPTIONS)
char *prefix, // Menu prefix (eg.: [*])
char *cursor, // Menu cursor (eg.: ->)
usint_t orient, /*
* Menu orientation vertical or horzontal.
* 0 or false for horizontal
* 1 or true for vertical
*/
usint_t padding, // Menu childrens padding (eg.: 3)
usint_t start_pos, // Menu set active child (eg.: 1)
usint_t delay, // Menu children switch delay
usint_t childs, // Number of childrens
... /*
* Variable list of arguments char* type.
* Name of the childrens.
*/
)
{
va_list args;
int tmp=0,pos;
char chr;
usint_t opt=start_pos;
char* format=malloc
(
(
strlen(name)+strlen(prefix)+strlen(cursor)+
3+ /* menu suffix (1 byte) and backspace (2 bytes) */
(2*childs)+ /* newline (2 bytes) times childs */
(padding*childs)+ /* number of spaces times childs */
childs*15 /* children name maxlen (15 bytes) times childs*/
)*sizeof(char)
);
do
{
if(tmp!=0)chr=getch();
if(chr==0x48||chr==0x4B)
(opt>1&&opt!=1)?opt--:(opt=childs);
else if(chr==0x50||chr==0x4D)
(opt>=1&&opt!=childs)?opt++:(opt=1);
else {/* do nothing at this time*/}
strcpy(format,"");
strcat(format,prefix);
strcat(format,name);
strcat(format,":");
va_start(args,childs);
for (tmp=1;tmp<=childs;tmp++)
{
(orient)?strcat(format,"\n"):0;
pos=padding;
while((pos--)>0) strcat(format," ");
if(tmp==opt)
{
strcat(format,"\b");
strcat(format,cursor);
}
strcat(format,va_arg(args,char*));
}
/*if(tmp!=childs)
{
fprintf(stderr,"%s: recieved NULL pointer argument,"
" child not named", __func__);
return -1;
}*/
Sleep(delay);
system("cls");
printf(format);
va_end(args);
}while((chr=getch())!=0x0D);
return opt;
}

Answer 2

May be you should try to use int x as a key to use a desirable command, may be like that:
while(x != 0)
{
scanf("%d", &x);
switch (x)
{
printf("input '2' to...\n");
printf("input '3' to...\n");
printf("input '4' to...\n");
printf("input '5' to...\n");
printf("input '6' to...\n");
case 1:
head = Enqueue(head);
break;
case 2:
head1 = spisokMagazinovScenoiMensheiZadannoi(head, head1);
break;
case 3:
head1 = udalenieElementa(head1);
break;
case 4:
head1 = addNewMagazin(head1);
break;
case 5:
head1 = addNewMagazin(head1);
break;
case 6:
printToTheFile(head);
break;
}
}
I used it in my previous homework. Hope it will be usefull for you

Answer 3

it's my exaple of func menu.
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <windows.h>
int menu(char s[][80],int kolop){
int pos = 0,push = 0,i,flag = 0;
printf("MENU:\n>");
puts(s[0]);
for(i = 1;i < kolop;i++){
printf(" ");
puts(s[i]);
}
printf("Enter 5 to move the cursor down 8 to the top(Press ENTER to end)\n");
do{
if(flag == 1)
printf("Error try to press 5,8 or ENTER\n");
push = getch();
flag = 1;
}
while(push != 56 && push != 53 && push != 13);
flag = 0;
system("cls");
while(push != 13){
if(push == 53){
puts("MENU:");
for(i = 0;i < kolop;i++){
if(i == pos + 1 && flag == 0){
printf(">");
puts(s[i]);
flag = 1;
pos++;
}
else{
printf(" ");
puts(s[i]);
}
}
}
if(push == 56){
puts("MENU:");
for(i = 0;i < kolop;i++){
if(i == pos - 1 && flag == 0){
printf(">");
puts(s[i]);
flag = 1;
pos--;
}
else{
printf(" ");
puts(s[i]);
}
}
}
_flushall();
printf("Enter 5 to move the cursor down 8 to the top(Press ENTER to end)\n");
flag = 0;
do{
if(flag == 1)
printf("Error try to press 5,8 or ENTER\n");
push = getch();
flag = 1;
}
while(push != 56 && push != 53 && push != 13);
flag = 0;
system("cls");
}
pos++;
return pos;
}
int main()
{
SetConsoleCP(1251);
SetConsoleOutputCP(1251);
char s[][80] = {"1","2","3","4","5","6","7"};
int i,pos = 0,push,flag = 0;
pos = menu(s,7);
printf("%d",pos);
//system("cls");
return 0;
}