Question

c语言实现一个功能：必须先输入1才能输入实现2.3功能，如果先输入2.3则提示请先输入1

Answer 1

#include<stdio.h>

void func1();
void func2();

int main()
{
int num;
while(1)
{
printf("please input num:\n");
scanf("%d",&num);
if(num==0)
break;
if(num>3||num<1)
continue;
switch(num)
{
case 1:
{
func1();
func2();
break;
}
case 2:
{
printf("please input 1\n");
break;
}
case 3:
{
printf("please input 1\n");
break;
}
}
}
return 0;
}

void func1()
{
printf("2\n");
}

void func2()
{
printf("3\n");
}