Just use a string a look up the appropriate entry:
char convert(int numberGrade ){
if (numberGrade >=0 && numberGrade <= 20) {
// 012345678901234567890
return "FFFFFFEEDDCCCBBBAAAAA"[numberGrade];
}
return 'X'
}
EDIT
Also you need to move the call to the convert function After you enter in the value.
See below:
int main(){
int note;
printf("Quelle est la note à convertir?\n");
scanf("%d", ¬e);
char lettre = convert(note);
printf("%c\n", lettre); // use %c with `char`, not %s
return 0;
}
solved Language C: convert a number grade into a letter grade