最初版本：
#include<stdio.h>
int checkPassword();
int add(int x,int y);
int sub(int x,int y);
int multi(int x,int y);
float quo(float x1,float y1);
int com(int x,int y);
int x,y;
int result;
int select;
float result1;
float x1,y1;
int success,psw;
int a;
int i;
int t;
void main()
{
printf("請輸入密碼:\n");
i=0;
do{
scanf("%d",&a);
if( a!=1234 && i<2)
printf("請重新輸入密碼:\n");
else
i=3;
i++;
}while( i<=2);
if(a==1234)
{
for(t=1;t!=6;t=select)
{
printf("+=============================+\n");
printf("+======計=算=器=主=菜=單======+\n");
printf("+=============================+\n");
printf("+==========1、 加法==========+\n");
printf("+==========2、 減法==========+\n");
printf("+==========3、 乘法==========+\n");
printf("+==========4、 除法==========+\n");
printf("+==========5、 求余==========+\n");
printf("+==========6、 退出==========+\n");
printf("+=============================+\n");
printf("請輸入你的選擇:\n");
scanf("%d",&select);
switch(select)
{
case 1:
printf("請輸入兩個數:\n");
scanf("%d%d",&x,&y);
result=add(x,y);
printf("%d+%d=%d\n",x,y,result);
break;
case 2:
printf("請輸入兩個數:\n");
scanf("%d%d",&x,&y);
result=sub(x,y);
printf("%d-%d=%d\n",x,y,result);
break;
case 3:
printf("請輸入兩個數:\n");
scanf("%d%d",&x,&y);
result=multi(x,y);
printf("%d*%d=%d\n",x,y,result);
break;
case 4:
printf("請輸入兩個數:\n");
scanf("%f%f",&x1,&y1);
result1=quo(x1,y1);
printf("%f/%f=%f\n",x1,y1,result1);
break;
case 5:
printf("請輸入兩個數:\n");
scanf("%d%d",&x,&y);
result=com(x,y);
printf("%d/%d=%d\n",x,y,result);
break;
case 6:
break;
default:
printf("請輸入1~5之間的數\n");
break;
}
}
}
}
int add(int x,int y)
{
int sum;
sum=x+y;
return sum;
}
int sub(int x,int y)
{
int sub;
sub=x-y;
return sub;
}
int multi(int x,int y)
{
int multi;
multi=x*y;
return multi;
}
float quo(float x,float y)
{
float quo;
quo=x/y;
return quo;
}
int com(int x,int y)
{
int com;
com=x%y;
return com;
}
int checkPassword( int psw)
{
if(psw==1234)
success=1;
else
success=-1;
return success;
}
改版後：
#include<stdio.h>
int yanzheng(int );
void caidan();
void jiafa(int,int);
void jianfa(int,int);
void chengfa(float,float);
void chufa(float,float);
void mo(int,int);
void main(){
int x,m;
int y;
float a,b;
printf("請輸入密碼:\n");
scanf("%d",&x);
m=yanzheng(x);
if(m==1){
caidan();
//int y;
//float a,b;
for(;y!=6;){
printf("請輸入選項:\n");
scanf("%d",&y);
if(y>=1 && y<6){
printf("請輸入要運算的兩個數:\n");
scanf("%f%f",&a,&b);
}
switch(y){
case 1 :jiafa(a,b);break;
case 2 :jianfa(a,b);break;
case 3 :chengfa(a,b);break;
case 4 :chufa(a,b);break;
case 5 :mo(a,b);break;
case 6 :break;
default : printf("選項輸入錯誤！請重試\n");break;
}
}
}
}
int yanzheng(int x){
int i,m;
for(i=1,m=0;i<3;i++){
if(x==1234){
m=1;
break;
}
printf("請重新出入密碼:");
scanf("%d",&x);
}
return m;
}
void caidan(){
printf("+=============================+\n");
printf("+======計=算=器=主=菜=單======+\n");
printf("+=============================+\n");
printf("+==========1、 加法==========+\n");
printf("+==========2、 減法==========+\n");
printf("+==========3、 乘法==========+\n");
printf("+==========4、 除法==========+\n");
printf("+==========5、 求余==========+\n");
printf("+==========6、 退出==========+\n");
printf("+=============================+\n");
}
void jiafa(int x,int y){
int sum;
sum=x+y;
printf("%d\n", sum);
}
void jianfa(int x,int y){
int cha;
cha=x-y;
printf("%d\n", cha);
}
void chengfa(float x,float y){
float ji;
ji=x*y;
printf("%f\n", ji);
}
void chufa(float x,float y){
float shang;
shang=x/y;
printf("%f\n", shang);
}
void mo(int x,int y){
int mo;
mo=x%y;
printf("%d\n", mo);
}
