New to C, gets problem

[Slave]

I find that this function

//letter counter
void letter_counter(void) {
int i = 0, counter = 0;
char word[80];
char letter, function;
printf("Type in a word: ");
gets(word);
printf("Type a letter: ");
scanf("%c", &letter);
while(word[i] != '\0') {
if(word[i] == letter) {
counter++;
}
i++;
}
printf("\nThat letter appeared %d time(s)\n", counter);
}

is producing "Type in a word: Type in a letter: _" (the underscore resembles 'waiting for input').

However having it in main with nothing else fixes the problem. ie:

#include <string.h>
#include <stdio.h>

int main() {
int i = 0, counter = 0;
char word[80];
char letter, function;
printf("Type in a word: ");
gets(word);
printf("Type a letter: ");
scanf("%c", &letter);
while(word[i] != '\0') {
if(word[i] == letter) {
counter++;
}
i++;
}
printf("\nThat letter appeared %d time(s)\n", counter);
}

The full program:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

void letter_counter(void);
void calculator(void);

int main() {
char function;
printf("Type in a function you would like to use: ");
printf("\nFor letter counter type \"l\"\n");
printf("For calculator type \"c\"");
printf("\n\nEnter a function: ");
while(function != 'e') {
scanf("%c", &function);
if(function == 'l') {
letter_counter();
printf("\nEnter another function or type \"e\" to exit: ");
} else if(function == 'c') {
calculator();
printf("\n\nEnter another function or type \"e\" to exit: ");
} else if(function == 'e') {
exit(0);
}
}
}

//letter counter
void letter_counter(void) {
int i = 0, counter = 0;
char word[80];
char letter, function;
printf("Type in a word: ");
gets(word);
printf("Type a letter: ");
scanf("%c", &letter);
while(word[i] != '\0') {
if(word[i] == letter) {
counter++;
}
i++;
}
printf("\nThat letter appeared %d time(s)\n", counter);
}

//calculator
void calculator(void) {
printf("For: Addition type \"a\"\n : Subtraction type \"s\"\n : Division type \"d\"");
char type;
printf("\n\nEnter calculation type: ");
scanf("%s", &type);
int i = 0, j = 0, k = 0, p = 0, g = 0, h = 0, u = 0, o = 0;
//addition
if(type == 'a') {
printf("\nEnter two numbers to add separated by a space: ");
scanf("%d %d", &i, &j);
i = i + j;
printf("Answer is: %d", i);
//subtraction
} else if(type == 's') {
printf("\nEnter two numbers to subtract separated by a space: ");
scanf("%d %d", &k, &p);
k = k - p;
printf("Answer is: %d", k);
//division
} else if(type == 'd') {
printf("\nEnter two numbers to divide separated by a space: ");
scanf("%d %d", &g, &h);
g = g / h;
printf("Answer is: %d", g);
//multiplication
} else if(type == 'm') {
printf("\nEnter two numbers to multiply separated by a space: ");
scanf("%d %d", &o, &u);
o = o * u;
printf("Answer is: %d", o);
}
}

Hope anyone can help :P
It's not a huge deal, but I really want to know why it's not working

[Adak]

Thanks for posting your code, and welcome to the forum, Slave.

Two things you need to know, right off:

1) Always put code tags around your program. In the edit window, highlight your code, and click on the # icon (right below the smilies pull down thingy.

2) Be sure you have some good indentation: compare these two snippets of your program

while(function != 'e') {
scanf("%c", &function);
if(function == 'l') {
letter_counter();
printf("\nEnter another function or type \"e\" to exit: ");
} else if(function == 'c') {
calculator();
printf("\n\nEnter another function or type \"e\" to exit: ");
} else if(function == 'e') {
exit(0);
}
}
}

and

while(function != 'e') {
   scanf("%c", &function);
   if(function == 'l') {
      letter_counter();
      printf("\nEnter another function or type \"e\" to exit: ");
   } 
   else if(function == 'c') {
      calculator();
      printf("\n\nEnter another function or type \"e\" to exit: ");
   } 
   else if(function == 'e') {
      exit(0);
   }
}

As you program more, your brain naturally becomes more skilled at reading code in the common indented formats. Lacking that, it's like walking through knee deep snow.

I'm still trying to wade through your code for your answer.

[Adak]

Slave, you got ambushed by the "leftovers in the keyboard buffer" trap.

You don't have it in main(), because you didn't go through the menu, and get the leftovers, built up.

Here's the fix:

//letter counter
void letter_counter(void) {
  int i = 0, counter = 0;
  char word[80];
  char letter, function;
  printf("Type in a word: ");
  /* this next line may be used for REALLY dirty keyboard input problems 
        while((letter = getchar()) != '\n');
  */

  letter = getchar(); //cleans out 1 char only but it's all you needed
  gets(word);
  printf("Type a letter: ");
  scanf("%c", &letter);
  while(word[i] != '\0') {
    if(word[i] == letter) {
      counter++;
    }
    i++;
  }
  printf("\nThat letter appeared %d time(s)\n", counter);
}

Before you ask, no, you can't use fflush(stdin). That works only when directed to outbound buffers, not inbound one's.

[RockyMarrone]

Hey this is the modification of your code

the scanf was not getting for letter it will work with this code

/*                                                                                                                                                                                                                
 * This function will work like fflush stdin to get                                                                                                                                                               
 * extra junk charachter into it                                                                                                                                                                                  
 */
void clear_kb(void) {
  char junk[80];
  gets(junk);
}


//letter counter                                                                                                                                                                                                  
void letter_counter(void) {
  int i = 0, counter = 0;
  char word[80] = {0};
  char letter;
  printf("Type in a word: \n");
  scanf( "%s", &word);
    clear_kb();

    printf("Type a letter: \n");
    scanf("%c", &letter);

    while(word[i] != '\0') {
      if(word[i] == letter) {
        counter++;
      }
      i++;
    }
    printf("\nThat letter appeared %d time(s)\n", counter);
}

[Slave]

Thanks guys for your replies.

In regards to indentation I was lazy after I pasted it screwed up the formatting :P I'll take more care next time and put tags around it.

These forums should be EXTREMELY helpful while I learn C ;D

Cheers.

[Elysia]

Never use gets: SourceForge.net: Gets - cpwiki