[Solved] Convert data from const void *data to double

#include <stdio.h> #include <string.h> double myfunction(const void *data){ double v; memcpy(&v, data, sizeof(v)); return v; } int main (int argc, char *argv[]) { unsigned char data[] = {0x40,0x20,0,0,0,0,0,0}; int i, len = sizeof(data); //reverse data If necessary for(i=0;i<len/2;++i){ unsigned char c = data[i]; data[i] = data[len -1 -i]; data[len -1 -i] = c; } double … Read more

[Solved] Why aren’t consecutively-defined variables in increasing memory locations?

There’s no reason for them to be, so the compiler does what’s best for itself. Complex compiler optimizations and efficient and linear memory layout don’t all go together, so linear memory layout was sacrificed. When you get to hashtables, you will learn how the most efficient algorithms lead to repeatable pseudo-random output order. The symbol … Read more

[Solved] strcat for dynamic char pointers

From section 7.20.3.2 The free function of the C99 standard: The free function causes the space pointed to by ptr to be deallocated, that is, made available for further allocation. If ptr is a null pointer, no action occurs. Otherwise, if the argument does not match a pointer earlier returned by the calloc, malloc, or … Read more

[Solved] Program stopped working, when tried to run

You have your main problem here. double *tabT1; double *tabT2; tabT1[0]=1; tabT1[1]=tabX[j]*(-1); tabT2[0]=1; tabT2[1]=tabX[i]*(-1); You haven’t allocated the memory, instead, you have just declared the double ptrs tabT1 and tabT2 and accessing them by pretending you have allocated. double *tabT1 = new double[2]; double *tabT2 = new double[2]; will fix this, however, I strongly suggest … Read more

[Solved] Why should I use pointers? C++

A pointer is an address of a variable. Imagine ram as consecutive boxes. Each box has an address. Now in your example. int a = 8; //declares a variable of type int and initializes it with value 8 int *p1; //p1 is a pointer meaning that the variable p1 holds an address instead of a … Read more

[Solved] C++ char getting errors? [closed]

These both statements are wrong char[] name = { “Nitish prajapati” }; char* namePointer = &name ; In C++ valid declaration of an array looks like char name[] = { “Nitish prajapati” }; As for the second statement then there is no implicit conversion from type char ( * )[17] to char *. The initializer … Read more

[Solved] Pointers and char[] in C [closed]

To know how all these three code blocks works, you got to start reading good C book specially array and pointers concept. Case 1 :- In the below code block int main(void) { char x[] = “gate2011”; char *ptr = x; printf (“%s”, ptr+ptr[3]-ptr[1]); return 0; } It looks like x[0] x[1] x[2] x[3] x[4] … Read more