Question

Ok, i’m writing in c here. Compiling in mingw gcc.

I’m trying to do something really simple. create a vector struct containing 3 floats x,y,z.

then I want to be able to do some math with them.

This is my short test program:

#ifndef _PHYSICS_C_
#define _PHYSICS_C_


    #define SUCCESS  0
    #define FAILURE  1


    typedef struct {
        float x;
        float y;
        float z;
    }vector;

    int add ( vector* a, vector* b, vector* destination ){
        (*destination).x = (float)( ((*a).x) + ((*b).x) );
        (*destination).y = (float)( ((*a).y) + ((*b).y) );
        (*destination).z = (float)( ((*a).z) + ((*b).z) );      
        return SUCCESS;
    }

    int main(int argc, char** argv){

        printf("creating vectors\n\n");
        vector a = {1.0f,5.0f,3.0f};
        vector b = {2.0f,3.0f,6.0f};
        vector destination;

        printf("adding vectors\n\n");
        if(add(&a, &b, &destination) == SUCCESS){       
            printf("result: (%d, %d, %d)\n\n",destination.x,destination.y,destination.z);
        } else {
            printf("the program failed somehow...\n\n");
        }

        printf("Press any key to continue...\n");
        getchar();

        return SUCCESS;
    }

#endif

When I compile and run it, it should return (3, 8, 9) the sum of vectors a and b.

instead it returns (0, 1074266112, 0)…

I can’t figure out what is wrong.

for some reason I think that I must somehow be writing over memory I’m not supposed to.

Answer 1

x,y,z are floats but you are trying to print them as integers.

try:

        printf("result: (%f, %f, %f)\n\n",destination.x,destination.y,destination.z);

check man printf or your documentation to see all of the specifiers for printf.