体验C语言内存操作的魅力之范型

#include <stdio.h>#include <stdlib.h>#include <assert.h>#include <string.h>#define BASE_LENGTH 4typedef struct{ void* elements; int elementSize; int allocSize; int pos;}Stack;void StackNew(Stack* s, int size) { s->elementSize = size; s->pos = 0; s->allocSize = size * BASE_LENGTH; s->elements = malloc(s->allocSize); assert(s->elements != NULL);}void StackPush(Stack* s, void* element) { if(s->pos == s->allocSize) { s->allocSize *= 2; s->elements = realloc(s->elements, s->allocSize); assert(s->elements); } void* next = (char*)s->elements + s->pos; memcpy(next, element, s->elementSize); s->pos += s->elementSize;}void StackPop(Stack* s) { if(s->pos == 0) { printf("Error: Stack is null\n"); return; } s->pos -= s->elementSize;}void StackFree(Stack* s) { free(s->elements);}int main() { Stack s; int i = 0; double d = 0.233; StackNew(&s, sizeof(double)); /*-------Test stack push-----*/ for(i = 0; i < 10; ++i) { d = d * 2; StackPush(&s, &d); } double *arr = s.elements; printf("\nafter push the num is:"); for(i = 0; i < s.pos/sizeof(double); ++i) { printf("%f\n", arr[i]); } /*-------Test stack pop------*/ StackPop(&s); printf("\nafter pop the num is:"); for(i = 0; i < s.pos/sizeof(double); ++i) { printf("%f\n", arr[i]); } StackFree(&s); return 0;}
程序编译环境是gcc version 4.2.1。全文完。