#include <stdio.h>
int main()
{
    int t1,t2;
    float weight,cost,price;
   
    printf("\n\n***********那欢迎进入中国民航国内运输规则行李托运费计算系统**********");
    printf("\n请选择你的机票类型\n");
    printf("\t 1成人票\n");
    printf("\t 2儿童票\n");
    printf("\t 3婴儿票\n");
    printf("请按1,2或者3来选择你的机票类型 ");
    scanf("%d\n",&t1);
    printf("\n请选择机票的等级\n");
    printf("\t 1.头等舱\n");
    printf("\t 2.公务舱\n");
    printf("\t 3.经济舱\n");
    printf("\n请按1,2或者3来选择你的机票等级 ");
    scanf("%d\n",&t2);
    printf("\n请输入你的行李重量(kg):\n");
    scanf("%f\n",&weight);
    printf("\n请输入经济舱的机票价格:\n");
    scanf("%f\n",&price);

    if(t1==1&&t2==1&&weight<=40)
        cost=0;
    if(t1==1&&t2==1&&weight>40)
        cost=(weight-40)*(price*0.015);
    if(t1==1&&t2==2&&weight<=30)
        cost=0;
    if(t1==1&&t2==2&&weight>30)
        cost=(weight-30)*(price*0.015);
    if(t1==1&&t2==3&&weight<=20)
        cost=0;
    if(t1==1&&t2==3&&weight>20)
        cost=(weight-20)*(price*0.015);
   
    if(t1==2&&t2==1&&weight<=40)
        cost=0;
    if(t1==2&&t2==1&&weight>40)
        cost=(weight-40)*(price*0.015);
    if(t1==2&&t2==2&&weight<=30)
        cost=0;
    if(t1==2&&t2==2&&weight>30)
        cost=(weight-30)*(price*0.015);
    if(t1==2&&t2==3&&weight<=20)
        cost=0;
    if(t1==2&&t2==3&&weight>20)
        cost=(weight-20)*(price*0.015);
    if(t1==3)
        cost=weight*(price*0.015);
   
    printf("%f\n",cost);
   
    [local]2[/local]
   
   
}

不知道为什么我运行程序的时候一定要按 1，才可以往下运行，而不是按1 回车运行，想不明白。而且运行之后还会直接跳过，出现乱码

后来我自己慢慢地再检查了一次，我自己就发现了，还是感谢大家的回答！