Scanf the numbers into function in C [closed] - c

Question

Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers.
This question was caused by a typo or a problem that can no longer be reproduced. While similar questions may be on-topic here, this one was resolved in a way less likely to help future readers.
Closed 2 years ago.
Improve this question
here is the code I wrote.
#include <stdio.h>
#include <stdlib.h>
typedef struct note {
int pitch;
int velocity;
int channel;
} note;
int printnote(int pitch, int velocity, int channel);
int main() {
int size = 100;
note note;
struct note *ptr = malloc(size * sizeof(int));
printf("Input the values for the `pitch`, `velocity`, and `channel`\n");
scanf("%d ％d %d", &note.pitch, &note.velocity, &note.channel);
printnote(note.pitch, note.velocity, note.channel);
free(ptr);
return 0;
}
int printnote(pitch, velocity, channel) {
printf("The MIDI Note is:\n");
printf("Pitch -> %d\n", pitch);
printf("velocity -> %d\n", velocity);
printf("channel -> %d\n", channel);
return 0;
};
When I run the code and type the numbers, it shows the wrong answers.
For example, I run the code, and it shows
Input the values for the `pitch`, `velocity`, and `channel`
5 5 5
The MIDI Note is:
Pitch -> 5
velocity -> 0
channel -> -429762432
The three numbers should be the same as the input numbers.
Can anyone help me?

Answer 1

There is a subtle typo in your scanf() conversion string:
scanf("%d ％d %d", &note.pitch, &note.velocity, &note.channel);
You used the unicode full width percent sign ％ (\uff05) instead of the ASCII % character. scanf does not recognise this as a conversion specifier and tries to match the byte sequence used to encode ％, (0xEF 0xBC 0x85 in UTF-8) and fails thus only converting the first input into note.pitch and leaving note.velocity and note.channel uninitialized, returning 1. Note how ％ looks different from % in the fixed font used for code, but identical in the font used for this text: ％ % ％ % ％ %.
Just replace ％ with the correct character:
scanf("%d %d %d", &note.pitch, &note.velocity, &note.channel);
Also note these remarks:
size and ptr are not used in main(),
you should check the return value of scanf() to detect invalid input. This check would have helped find the error,
the prototype in the definition of printnote is incorrect: the argument types are missing,
the ; after the } is useless,
using the same identifier note for the variable and its type is confusing.
Here is modified version:
#include <stdio.h>
typedef struct note {
int pitch;
int velocity;
int channel;
} note;
void printnote(int pitch, int velocity, int channel);
int main() {
note note1;
printf("Input the values for the `pitch`, `velocity`, and `channel`\n");
if (scanf("%d %d %d", &note1.pitch, &note1.velocity, &note1.channel) != 3) {
printf("invalid input\n");
return 1;
}
printnote(note1.pitch, note1.velocity, note1.channel);
return 0;
}
void printnote(int pitch, int velocity, int channel) {
printf("The MIDI Note is:\n");
printf("pitch -> %d\n", pitch);
printf("velocity -> %d\n", velocity);
printf("channel -> %d\n", channel);
}