Trying to return either a sum or average by user input

Hey I have written the below code:

# include <stdio.h>
# include <stdlib.h>
#include <string.h>
#include <cs50.h>

int main(void)
{
    int *hours_worked;
    int size;
    int suma = 0;

    printf("Enter the number of weeks you have taken CS50: ");
    scanf("%d", &size);

    hours_worked = (int*) malloc(size * sizeof(int));

    if(hours_worked == NULL)
    {
        printf("Memory Allocation failed!");
        return 1;
    }
    for (int i=0; i<size; i++)
    {
    printf("Week %i ", i);
    hours_worked[i] = get_int("HW Hours :\n");
    }

    //calculez suma

    for (int i = 0; i < size; i++)
    {
        suma = suma + hours_worked[i];
    }
    float average = suma / size;

    char *value = (char*) malloc(sizeof(char));
    if(value == NULL)
    {
        printf("Memory Allocation failed!");
        return 1;
    }
    *value = '
# include <stdio.h>
# include <stdlib.h>
#include <string.h>
#include <cs50.h>
int main(void)
{
int *hours_worked;
int size;
int suma = 0;
printf("Enter the number of weeks you have taken CS50: ");
scanf("%d", &size);
hours_worked = (int*) malloc(size * sizeof(int));
if(hours_worked == NULL)
{
printf("Memory Allocation failed!");
return 1;
}
for (int i=0; i<size; i++)
{
printf("Week %i ", i);
hours_worked[i] = get_int("HW Hours :\n");
}
//calculez suma
for (int i = 0; i < size; i++)
{
suma = suma + hours_worked[i];
}
float average = suma / size;
char *value = (char*) malloc(sizeof(char));
if(value == NULL)
{
printf("Memory Allocation failed!");
return 1;
}
*value = '\0';
if (strcmp(value, "T") != 0 || strcmp(value, "A") != 0)
{
*value = get_char("Enter T For total hours, A for average hours per week: ");    
}
else if (strcmp(value, "T") == 0)
{
printf("Total hours worked: %i\n", suma);
}
else 
{
printf("This week you worked on average: %f", average);
}
free(value);
free(hours_worked);
}
';
    if (strcmp(value, "T") != 0 || strcmp(value, "A") != 0)
    {
        *value = get_char("Enter T For total hours, A for average hours per week: ");    
    }

    else if (strcmp(value, "T") == 0)
    {
        
        printf("Total hours worked: %i\n", suma);
    }
    else 
    {
        printf("This week you worked on average: %f", average);
        
    }
    free(value);
    free(hours_worked);
}

I am trying to get either a sum or average based on user input. User enters numbers of weeks, the code calculates sum of either weeks or average, but fails to share the result.
Any ideas how you would do this different?

I was expecting to see this:

$ ./test
Number of weeks taking CS50: 3
Week 0 HW Hours: 3
Week 1 HW Hours: 7
Week 2 HW Hours: 10
Enter T for total hours, A for average hours per week: A
6.7 hours

or

$ ./test
Number of weeks taking CS50: 2
Week 0 HW Hours: 2
Week 1 HW Hours: 8
Enter T for total hours, A for average hours per week: T
10.0 hours

In C, a string is defined as a sequence of nonzero bytes followed by a zero value byte (the null character byte, '\0').

The string "T" consists of two bytes: 'T' and '\0'.

The zero byte works as a sentinel value, allowing functions like strstr and strcmp to know how long a string is without you needing to provide that information explicitly.

Passing a non-null terminated sequence to a function like strcmp invokes Undefined Behaviour, as the function no longer knows when to stop reading characters, and will carry on reading adjacent memory locations until it finds a zero byte, trips something that crashes your program, or lights your keyboard on fire.

In

char *value = (char*) malloc(sizeof(char));
if(value == NULL)
{
    printf("Memory Allocation failed!");
    return 1;
}
*value = '\0';
if (strcmp(value, "T") != 0 || strcmp(value, "A") != 0)
{
*value = get_char("Enter T For total hours, A for average hours per week: ");    
}
else if (strcmp(value, "T") == 0)
/* ... */

value can only contain the empty string, having room for only the null byte.

You manage to avoid undefined behaviour by only comparing an empty string against the strings "T" and "A", before overwriting the null byte with another character, at which point value is no longer a string if the user provides anything other than the null byte.

The comparison in the else if condition can never occur, luckily.

It would be easier to read a single character and compare it directly against 'T' or 'A', avoiding strcmp all together.

Alternatively, use get_string, but watch out that it can return the value NULL, which should not be passed to strcmp.

Otherwise, here is a rather clunky example of manually building a string of a known length:

#include <cs50.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void)
{
    int length = 0;

    while (length < 1)
        length = get_int("Enter string length: ");

    char *str = malloc(1 + length);

    if (!str) {
        perror("malloc");
        return EXIT_FAILURE;
    }

    for (size_t i = 0; i < length; i++)
        str[i] = get_char("Enter character: ");

    str[length] = '\0';

    if (0 == strcmp(str, "hello"))
        puts("hi");
    else
        puts(str);

    free(str);
}

Note that in float average = suma / size;, both suma and size are integers, so this will perform integer division, truncating the result.

Only after the division is the value converted to a float. You should explicitly convert one of the operands beforehand with a cast (suma / (float) size). The other operand will be converted implicitly.

Unless you want to recall the values entered, there is no need to allocate additional memory, as you can perform your sums as you go.

Here is an example that requires storing the inputs in order to display them later.

#include <cs50.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    int weeks = get_int("Enter the number of weeks you have taken CS50: ");
    
    if (weeks < 1) {
        puts("You should get started!");
        return EXIT_SUCCESS;
    }

    int *hours = malloc(sizeof *hours * weeks);

    if (!hours) {
        perror("malloc");
        return EXIT_FAILURE;
    }

    int total = 0;

    for (int i = 0; i < weeks; i++) {
        hours[i] = get_int("Week %d HW hours: ", i);
        total += hours[i];
    }

    float average = total / (float) weeks;

    char selection = get_char("Enter T For total hours, A for average hours per week, W for weekly hours: ");

    if ('T' == selection)
        printf("Total hours: %d\n", total);
    else if ('A' == selection)
        printf("Average hours: %.2f\n", average);
    else if ('W' == selection)
        for (int i = 0; i < weeks; i++)
            printf("Week %d HW hours = %d\n", i, hours[i]);

    free(hours);
}

nter the number of weeks you have taken CS50: 5
Week 0 HW hours: 4
Week 1 HW hours: 2
Week 2 HW hours: 5
Week 3 HW hours: 4
Week 4 HW hours: 6
Enter T For total hours, A for average hours per week, W for weekly hours: W
Week 0 HW hours = 4
Week 1 HW hours = 2
Week 2 HW hours = 5
Week 3 HW hours = 4
Week 4 HW hours = 6