实验：创建两条线程，线程的执行函数是取钱，（本实验有3个文件，其中account.c 和 account.h 文件是模拟银行取钱，存钱，查询余额的函数，test.c为主函数。由于账户里有10000元，两个人去取钱，结果同时取到了10000元
源码如下：
account.c
#include "account.h"#include <assert.h>#include <malloc.h>#include <string.h>Account *create_account(int code, double balance){ Account *r=(Account *)malloc(sizeof(Account)); assert(r!=NULL); r->code=code; r->balance=balance; return r;}void destroy_account(Account *a){ assert(a!=NULL); free(a);}double with_draw(Account *a, double amt){ assert(a!=NULL); if(amt > a->balance || amt<0){ return 0.0; } double balance=a->balance; sleep(1); balance = balance - amt; a->balance = balance; return amt;
}
double depoist(Account *a, double amt){ assert(a!=NULL); if(amt<0){ return 0.0; } double balance=a->balance; sleep(1); balance = balance + amt; a->balance = balance; return amt;}double get_balance(Account *a){ double balance = 0.0; balance=a->balance; return balance;
}
account.h
#ifndef __ACCOUNT_H__#define __ACCOUNT_H__typedef struct{ int code; double balance;}Account;extern Account * create_account(int code,double balance);extern void destroy_account(Account *a);extern double with_draw(Account *a,double amt);extern double depoist(Account *a,double amt);extern double get_balance(Account *a);
#endif
test.c
#include <pthread.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include "account.h"typedef struct{ char name[20]; Account *account; double amt;}Arg;void *func_th(void *arg){ Arg *r=(Arg *)arg; double amt=with_draw(r->account,r->amt); printf("%8s(0x%lx) withdraw %f from account %d\n", r->name,pthread_self(),amt,r->account->code); return (void*)0;}int main(int argc,char *argv[]){ int err; pthread_t boy,girl; Account *a=create_account(1001,10000); Arg r1,r2; strcpy(r1.name,"man"); r1.account=a; r1.amt=10000;
strcpy(r2.name,"woman");
r2.account=a; r2.amt=10000; if((err=pthread_create(&boy,NULL,func_th,(void *)&r1))!=0) { perror("pthread create error"); } if((err=pthread_create(&girl,NULL,func_th,(void *)&r2))!=0) { perror("pthread create error"); } pthread_join(boy,NULL); pthread_join(girl,NULL); //打印余额 printf("the rest of the count is %f\n",get_balance(a)); //打印线程ID printf("%lx thread finished\n",pthread_self());
return 0;
}
程序运行结果：
woman(0x7fe943c15700) withdraw 10000.000000 from account 1001 man(0x7fe944416700) withdraw 10000.000000 from account 1001the rest of the count is 0.0000007fe944c19700 thread finished
