I am trying to pass a C char array to a function via its pointer and then accessing the char array in the function. At the moment I can only seem to access the first character and the rest is just random bytes. I have been trying to check the variables before and after the… Read More Accessing a C char array from a pointer

In my C program, I am trying to convert .asm code to pseudo-machine code. Assembly file used: ORG 0x10 start WB 0x05 ; write 0x05 to MBR WM 0x400 ; write data on MBR to memory at address 0x400 WB 0x03 ; write 0x03 to MBR WM 0x401 ; write data on MBR to memory… Read More C program fails executing upon removing unused malloc for char** Array on Windows only

Let’s say I have the following bit of code, which tries to ‘downcast’ a double value into a uint8_t: uint8_t downcast(uint8_t *down1, uint8_t *down2) { //the usual nullptr checks double fval = 100.0; //fits the uint8_t domain range *down1 = (uint8_t)fval; //should work… fval = 1000.0; //does not fit uint8_t domain range *down2 = (uint8_t)fval;… Read More downcasting a double/float to a uint8_t

I was implementing a basic getline() function for reading content of file and writing it to terminal however this works completely fine #include<stdlib.h> int main(int argc , char *argv[]) { FILE *fp = fopen(argv[argc-1],"r"); if(fp == NULL) { printf("error : can’t open file"); exit(1); } char *buf = NULL; size_t linelen = 0; size_t linecapp… Read More segfault in using getline() function in C

I want to know whether the statement int i; is a declaration or a definition. It seems that if a variable is not initialized outside the function, it is declared, but inside the function it must be defined. Is this really the case? If I write this statement multiple times outside the function, it compiles.… Read More int i; Is it a declaration or a definition?

I’m writing a factorial function for practice. On main I declare the variables and call it like this: int main(){ unsigned long n = 0; scanf("%lu", &n); unsigned long result = factorial(n); printf("%lu \n", result); return 0; } Which works and gives the result I want. But I thought it looked kinda bad so I… Read More C function gives wrong result when function call on main is refactored

This is some code I wrote to exercise using malloc(). In particular, I want to have a char-array of dimension and elements given by the user and to print these elements. #include <stdio.h> #include <stdlib.h> int main() { char *ptr; int d; printf("Inserire la dimensione dell’array CHAR:\n"); scanf("%d", &d); ptr = (char *) malloc(d *… Read More A warning I don't understand using malloc() in C language

Can I first allocate a struct (with a function inside) to a void* and trigger the function inside them. struct func { void (*fp)(); // this is a function }; struct thread{ void *stack; // I’m gonna use this to store ‘struct func’ above }; void assign(struct thread *t,void *f()){ struct func *task = (struct… Read More call a function inside struct but struct inside a void*

I am working on a problem, I have a variable and I have to use inside of for loops for(i=0;i<y*2+1;i++) { . . . } if I use like that does the processor speed decrease? Is there any disadvantage? does the processor speed decrease in embeeded C? Is there any disadvantage? >Solution : Readability and… Read More For loops in embeeded C

Pointers-to-array (not array pointers) are a lesser-known feature of the C programming language. int arr[] = { 3, 5, 6, 7, 9 }; int (*arr_ptr)[5] = &arr; printf("[2]=%d", (*arr_ptr)[2]); They allow you to "un-decay" a dynamically allocated array pointer. (which is pretty cool in my opinion) int *ptr = malloc(sizeof(int) * 5); int(*arr_ptr)[5] = (int(*)[5])ptr;… Read More How to return a Pointer-To-Array from a function in C?