Set variables by using fgetc(stdin)

Question

I am trying to set variables by using fgetc() from stdin.

Here's my code so far,

#include <stdio.h>

int main(void){
    int ch;
    int firstNumber,secondNumber;
    char str;

    printf("Enter two numbers and a string: ");
    while((ch=fgetc(stdin))!='\n'){
        while(ch != ' '){
            firstNumber = ch;
            secondNumber = ch;
            string = ch;
            }
        }
    printf("%d %d %s",firstNumber,secondNumber,string);
    return 0;
}

Therefore, if I type 2 2 string (there's whitespace between characters)

I want variable firstNumber to be 2

and secondNumber to be 2

and str to be string

Answer 1

Here is the possible approach:

1. You can parse the entire string first and store it into temporary buffer.
2. You can now use strtok() to tokenize the string using ' '(space) character. Alternatively, you can use sscanf() instead of strtok().
3. Use atoi() for first two numbers and read the final string.

Code:

Assuming that the buffer required to store scanned string doesn't exceed 100 bytes.

Approach using strtok():

int main()
{
    int ch,i=0;
    int firstNumber,secondNumber;
    const char seperator[2] = " -";
    char buffer[100];
    char *string;

    printf("Enter two numbers and a string: ");
    while((ch=fgetc(stdin))!='\n'){
        buff[i++]=ch;
    }

    /* get the first token as a number */
    firstNumber = atoi(strtok(buff, seperator));
    printf("%d\n",firstNumber);

    /* get the second token as a number*/   
    secondNumber = atoi(strtok(NULL, seperator));    
    printf("%d\n",secondNumber);

    /* get the third token as a string */
    string=strtok(NULL, seperator);
    printf("%s\n",string);

    return(0);
}

Approach using sscanf():

printf("Enter two numbers and a string: ");
while((ch=fgetc(stdin))!='\n'){
    buff[i++]=ch;
}

sscanf(buff, "%d %d %s", &firstNumber, &secondNumber, string);  
printf("%d\n%d\n%s\n", firstNumber, secondNumber, string);