Thread: show the menu only once each time..

when i input a number which is out of range it prints the menu again so in a single letter case.
but when i input "abc" it prints the menu 3 times in fact the number of menu print
depends on the number of chars in the strings.
how to do tat no matter what wrong input i will give it,it will print the menu again only once??

Code:

#include <stdio.h>

#define N 9

void mainMenu();


int main()
{
    char input[40];
    char input2[40];
    char board[N][N];
    mainPlayGame(board);
    printf("bye, please press enter to exit!\n");
   getchar();
   return 0;
}

void mainPlayGame(board){
    int opt,leng,size=-1;
  int index,kndex;
    char input[40];
    char ch_cords[40];
    char input2[40];
    int tr;
    int cords[8][2];
    int tndex;

    int i,k,j,ch,l;

    int  leng2;
    do
    {
      mainMenu();

    scanf("%d",&opt);
    l=getchar();
     if (opt==1)
     {
         printf("1");
     }
     if (opt==2)
    {
        printf("2");
     }
     if (opt==3)
     {
          printf("3");
     }
     if (opt==4)
     {
        printf("4");
     }
     if (opt==5)
    {
       printf("5");
     }
     if (opt==0){
     }
    }while(opt!=0);
}

int playGame(char board[N][N],int size){

}

void mainMenu() {


 printf("--------------------------\n");
printf("welcome to the game\n");
printf("1. choose board size\n");
printf("2. place mines\n");
printf("3. remove mines\n");
printf("4. show mines\n");
printf("5. start the game\n");
printf("0. exit\n");
printf("please enter your choice (input control is needed): \n");

}