Problem with functions in C (readability) - c

Question

I am working on an exercise in cs50 pset2 readability, and I'm trying to count up how many sentences there are in a text. So far my code is this:
#include<stdio.h>
#include<cs50.h>
#include<string.h>
#include<stdbool.h>
#include<ctype.h>
int isdelim(char c, int sentences)
int main (void)
{
string text = get_string("Text: ");
int sentences = 0;
for(int i = 0; i < strlen(text);i++)
{
sentences = isdelim(text[i], sentences);
}
printf("Sentences: %i\n", sentences);
}
int isdelim(char c, int sentences)
{
return c == '.' || c == '!' || c == '?';
sentences++;
}
But when I do ./readability and I type the text: Hello, world! Beautiful day!, it gives an output of: Sentences:0.
I am new to C so I can't really understand all these functions. I tried searching the web and using other external sources, but nothing makes sense. If you show me the answer, please make sure to tell me why it works, so I can learn. I may need the knowledge in the future. Thanks a lot.

Answer 1

There's several problems.
When you execute a return statement, the function ends. Nothing after that will be executed. So sentences++ is never executed.
In C, function parameters are passed by value. So incrementing sentences in the isdelim() function will not affect the variable in main().
int delim(char c, int sentences); is a function declaration, not a function call. Function calls don't include the type declarations.
You can solve the first problem by using an if statement that checks the condition, rather than returning the result of the condition immediately.
You can solve the second problem by passing a pointer to the variable and dereferencing it, or by having the function return the new value of sentences.
#include<stdio.h>
#include<cs50.h>
#include<string.h>
#include<stdbool.h>
#include<ctype.h>
int isdelim(char c, int sentences);
int main (void)
{
string text = get_string("Text: ");
int sentences = 0;
for(int i = 0; i < strlen(text);i++)
{
sentences = isdelim(text[i], sentences);
}
printf("Sentences: %i\n", sentences);
}
int isdelim(char c, int sentences)
{
if (c == '.' || c == '!' || c == '?') {
sentences++;
}
return sentences;
}

Answer 2

#Baramar makes some good points but I think the code could use a refactoring. The isdelim function is confusing. It's named as a Boolean function, so it should return a bool. And that function shouldn't take a sentences parameter; rather, let the caller handle the incrementing. And I've taken the liberty to call strlen before the loop so it doesn't get recomputed on each iteration. So:
#include<stdio.h>
#include<cs50.h>
#include<string.h>
#include<stdbool.h>
#include<ctype.h>
bool isdelim(char c);
int main (void)
{
string text = get_string("Text: ");
int sentences = 0;
int length = strlen(text);
for (int i=0; i<length; i++)
{
if (isdelim(text[i]))
{
sentences++;
}
}
printf("Sentences: %i\n", sentences);
}
bool isdelim(char c)
{
return c == '.' || c == '!' || c == '?';
}