testVector.c

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define ElemType double
#define ERROR -2
#define MISMATCH -3  //(维数)不匹配
#define UNORDERED -4 //不能用顺序法求解
#define STRANGE 5    //矩阵奇异
#define E 1.0e-2     //相对误差限

typedef struct
{
    int dimension;  //维数
    ElemType *elem; //向量,一维数组
} Vector;

//输入&V，n；初始化n维向量V（用1~n):
void VectorInit(Vector *v, int n)
{
    v->dimension = n;

    v->elem = (ElemType *)malloc(sizeof(ElemType) * (n + 1));
    return;
}

//复制向量
void VectorCopy(Vector V, Vector *x)
{
    if (V.dimension != x->dimension)
        exit(MISMATCH);
    for (int i = 1; i <= V.dimension; ++i)
    {
        (x->elem)[i] = V.elem[i];
    }
    return;
}

//打印向量
void PrintVector(Vector V)
{
    for (int i = 1; i <= V.dimension; ++i)
    {
        printf("%lf ", V.elem[i]);
    }
    printf("\n");
    return;
}

//向量数乘，V=向量U*数k（要求V已经初始化），传入V的指针，改变V后，返回V的指针
Vector *Vector_Num(Vector U, double k, Vector *v)
{
    if (U.dimension == v->dimension)
    {
        for (int i = 1; i <= U.dimension; ++i)
        {
            v->elem[i] = U.elem[i] * k;
        }
    }
    else
    {
        exit(MISMATCH);
    }
    return v;
}

//向量内积
double DotProduct(Vector X, Vector Y)
{
    if (X.dimension == Y.dimension)
    {
        double p = 0;
        for (int i = 1; i <= X.dimension; ++i)
        {
            p += X.elem[i] * Y.elem[i];
        }
        return p;
    }
    else
    {
        exit(MISMATCH);
    }
}
int main()
{
    Vector a;
    VectorInit(&a, 5);
    a.elem[1] = 1;
    a.elem[5] = 5;
    PrintVector(a);
    Vector b;
    VectorInit(&b, 5);
    Vector_Num(a, 2, &b);
    PrintVector(b);
    printf("dot product a,b: %lf", DotProduct(a, b));
    printf("dot product b,a: %lf", DotProduct(b, a));
    return 0;
}