When printing a string length using a character array with a for the first iteration does nothing, why?

Asked Feb 23 '17 at 22:23

Active Feb 23 '17 at 22:30

Viewed 31 times

I have this code, I'm trying to introduce n number of texts using fgets() and then know what's the length with a while and print this value (later i would do other things with this) but the first iteration always prints "0" without doing the fgets call and i want to know why and how to fix it.

#include <stdio.h>
int main(){
    int n;
    scanf("%d", &n);

    int i;
    for(i=0; i<=n; i++){
        char texto[50];
        fgets(texto, 50, stdin);
        int length = 0;
        while(texto[length]!='\n'){
            length++;
        }
        printf("%d\n", length); 
    }
    return 0;
}

edited Feb 23 '17 at 22:30

melpomene

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asked Feb 23 '17 at 22:23

Diego Castagne

7

Because the initial `scanf` is leaving the newline in the stream. This thing is asked here like 50 times a day. – Eugene Sh. Feb 23 '17 at 22:26
The first `fgets(texto, 50, stdin);` will read an empty string because the previous `scanf("%d", &n);` has left a newline in the input buffer. Please do not mix your input methods. – Weather Vane Feb 23 '17 at 22:27
Why do you mix `scanf()` and `fgets()`? You should use one of them, be consistent that will avoid some unexpected behavior. – Stargateur Feb 23 '17 at 22:27
... and with scanf it is pretty difficult to not have unexpected behaviour. – Antti Haapala -- Слава Україні Feb 23 '17 at 22:47

When printing a string length using a character array with a for the first iteration does nothing, why?

0 Answers0