fixed :)

Well after a few hours with it this morning I have fixed all the bugs and answered my own questions, here is the corrected code if anyone wants to see it.

Code:

#include <stdio.h>
main()
{
 int a;
 printf("1.FOR loop\n2.WHILE loop\n3.DO-WHILE loop\nSelect a loop to preform:");
 scanf("%d",&a);
 switch(a){
  case 1:
   FORloop();
   break;
  case 2:
   WHILEloop();
   break;
  case 3:
   DOWHILEloop();
   break;
  default:
   printf("Bad input, quitting.\n");
   break;
 }
 getchar();
}
FORloop()
{
 int b;
 for(b=0;b<11;b++){
  printf("%d\n",b);
 }
}
WHILEloop()
{
 int c=0;
 while(c<11){
 printf("%d\n",c);
 c++;
 }
}
DOWHILEloop()
{
 int input,d=0;
 printf("1.Good loop\n2.Bad loop\nI'll explain later ;) pick one:");
 scanf("%d",&input);
 if(input==1){
  dwloop();
 }
 else if(input==2){
  do{
   printf("The explanation is in the source :)\n");
  }while(d!=0);  /*notice how it runs the "do" once even though the conditional statement is false*/
 } 
 else{
  printf("Bad input, quitting.\n");
 }
}
dwloop()
{
 int e=0;
 do{
  printf("%d\n",e);
  e++;
 }while(e!=11);
}

lol that was supposed to be the reply to what I thought was the thread I had posted this morning which was actually just the preview of the thread I was intending on posting.

made it a little more effiecent

Code:

#include <stdio.h>
main()
{
 int a;
 printf("1.FOR loop\n2.WHILE loop\n3.DO-WHILE loop\nSelect a loop to preform:");
 scanf("%d",&a);
 switch(a){
  case 1:
   FORloop();
   break;
  case 2:
   WHILEloop();
   break;
  case 3:
   DOWHILEloop();
   break;
  default:
   printf("Bad input, quitting.\n");
   break;
 }
 getchar();
}
FORloop()
{
 int b;
 for(b=0;b<11;b++){
  printf("%d\n",b);
 }
}
WHILEloop()
{
 int c=0;
 while(c<11){
 printf("%d\n",c);
 c++;
 }
}
DOWHILEloop()
{
 int input,d=0;
 printf("1.Good loop\n2.Bad loop\nI'll explain later ;) pick one:");
 scanf("%d",&input);
 if(input==1){
  do{
   printf("%d\n",d);
   d++;
  }while(d!=11);
 }
 else if(input==2){
  do{
   printf("The explanation is in the source ;)\n");
  }while(d!=0);  /*notice how it runs the "do" once even though the conditional statement is false*/
 } 
 else{
  printf("Bad input, quitting.\n");
 }
}

As it is it's only working because a lack of return type is defaulting to int, and a missing function prototype is defaulting to a function taking no args and returning int. Functions should have return types and their prototype at least must appear before first use.

At best this code will throw out a lot of warnings, and will probably often fail to compile, depending on the compiler and it's settings.

Well done learning about loops though. Next, try learning to pass parameters to functions.

Do you mean I should have

Code:

return 0;

in each function as good practice?