Counting vowels in text without arrays (C) - c

Question

i have to write a program that counts all vowels in a text & gives out the percentage of every vowel for the whole text.
For whatever reason we are not allowed to use arrays, but instead should do it with getchar().
#include <stdio.h>
#include <ctype.h>
int main() {
int current;
int cntAll = 0;
int cntA = 0, cntE = 0, cntI = 0, cntO = 0, cntU = 0;
int pA = 0, pE = 0, pI = 0, pO = 0, pU = 0;
printf("Enter Text: ");
while ((current = getchar()) != EOF){
if (isspace(current)) continue; // check for whitespace, if whitespace continue
else {
switch (current) { // check for vowel & increase vowelcount
case 'a':
cntA += 1;
case 'A':
cntA += 1;
case 'e':
cntE += 1;
case 'E':
cntE += 1;
case 'i':
cntI += 1;
case 'I':
cntI += 1;
case 'o':
cntO += 1;
case 'O':
cntO += 1;
case 'u':
cntU += 1;
case 'U':
cntU += 1;
}
}
cntAll++;
}
pA = (cntA / cntAll) * 100;
pE = (cntE / cntAll) * 100;
pI = (cntI / cntAll) * 100;
pO = (cntO / cntAll) * 100;
pU = (cntU / cntAll) * 100;
printf("\nLetters: %d\nPercentage A: %d\nPercentage E: %d\nPercentage I: %d\nPercentage O: %d\nPercentage U: %d\n",cntAll,pA,pE,pI,pO,pU);
system("PAUSE");
return 0;
}
Increasing the cntAll value works without problems, but it doesn't count the individual vowels for whatever reason.
Would appreciate any help!
Edited:
#include <stdio.h>
#include <ctype.h>
int main() {
int current;
int cntAll = 0;
int cntA = 0, cntE = 0, cntI = 0, cntO = 0, cntU = 0;
double pA = 0, pE = 0, pI = 0, pO = 0, pU = 0;
printf("Enter Text: ");
while ((current = getchar()) != EOF){
if (isspace(current)) continue;
else {
switch (current) {
case 'a':case 'A':
cntA += 1;
break;
case 'e':case 'E':
cntE += 1;
break;
case 'i':case 'I':
cntI += 1;
break;
case 'o':case 'O':
cntO += 1;
break;
case 'u':case 'U':
cntU += 1;
break;
}
}
cntAll++;
}
pA = 100.0 * cntA / cntAll;
pE = 100.0 * cntE / cntAll;
pI = 100.0 * cntI / cntAll;
pO = 100.0 * cntO / cntAll;
pU = 100.0 * cntU / cntAll;
printf("\nLetters: %d\nPercentage A: %.2lf\nPercentage E: %.2lf\nPercentage I: %.2lf\nPercentage O: %.2lf\nPercentage U: %.2lf\n",cntAll,pA,pE,pI,pO,pU);
system("PAUSE");
return 0;
}
cheers

Answer 1

You need to insert break statements between the cases.
Otherwise the program will execute all the statements below the one first entered. Actually this is a good feature. It allows you to consider multiple labels at the same time. Putting this together you get:
switch (current){
case 'a': case 'A':
cntA += 1;
break; // Don't follow through to the other cases.
case 'b': case 'B': /*etc*/
After this, note that (cntA / cntAll) * 100; will evaluate the expression in parentheses in integer arithmetic, which will truncate it to 0 in most cases. The fix is to write it as
100 * cntA / cntAll;
This will still truncate to an integer. If that's not tolerable then consider using the floating point expression 100.0 * cntA / cntAll and change your printf formatters accordingly. Using floating point is arguably better anyway as it obviates the potential for overflow when evaluating 100 * cntA.

Answer 2

case labels falls through to the next one below it without a break.
So if you read an 'a' then all the cases in your switch will be executed.
You need something like
switch (current) { // check for vowel & increase vowelcount
case 'a':
cntA += 1;
break; // <-- Note break here
...

Answer 3

First thing i notice is that you are missing break on every switch case. This will lead to wrong behaviour.
Second thing:
pA = (cntA / cntAll) * 100;
will calculate cntS/cntAll first which is <0. This value will be interpreted as integer so you always have 0*100 which is 0. You can rewrite it as
pA = (cntA * 100 ) / cntAll;
In that case you don't have to cast to float to get the right result. Note that for large cntA you may overflow.