C中未声明的标识符
我正在尝试在Visual Studio 2012 Express中用C编译一个小型银行程序。 它向我显示了几乎所有变量的这个错误“未声明的标识符”，这也是“语法错误：缺少’;’ 在’type’之前。“请告诉我正确的语法。谢谢。
#include #include int main() { printf("Welcome to skybank\n"); int deposit,withdraw,kbalance; char option; printf("Press 1 to deposit cash\n"); printf("Press 2 to Withdraw Cash\n"); printf("Press 3 to Know Your Balance\n"); scanf_s("%c",option); int decash,wicash; switch(option) { int balance; printf("Enter your current Balance\n"); scanf_s("%d",&balance); case 1: printf("Enter the amount you want to deposit\n"); scanf_s("%d",&decash); printf("Thank You\n"); printf("%d have been deposited in your account\n",decash); break; case 2: printf("Enter the amount you want to withdraw\n"); scanf_s("%d",&wicash); int wibal; wibal=balance-wicash; printf("Thank You\n"); printf("%d have been withdrawed from your account\n",wicash); printf("Your balance is %d\n",wibal); break; case 3: printf("Your balance is Rs.%d\n",balance); break; default: printf("Invalid Input\n"); break; } getchar(); } Microsoft C编译器仅支持该语言的25年版本。 其中一个限制是所有变量必须在任何其他语句之前声明。 因此，将所有变量声明移动到函数的顶部。
我能看到的下一个错误是使用带有%c格式字符串的scanf_s 。 您必须将指针传递给变量，并传递要读取的字符数。
scanf_s("%c", &option, 1);
同样，你需要传递一个地址来读取balance 。
您还需要更改switch语句，以便它只包含案例。 将裸指令移到外面。
您阅读option将无效。 因为当您检查1您正在使用ASCII代码检查字符1.将option更改为int并使用%d读取。
也许你正在寻找这样的东西：
#include #include int main(void) { int deposit,withdraw,kbalance; int option; int decash,wicash; int balance; int wibal; printf("Welcome to skybank\n"); printf("Press 1 to deposit cash\n"); printf("Press 2 to Withdraw Cash\n"); printf("Press 3 to Know Your Balance\n"); scanf_s("%d", &option); printf("Enter your current Balance\n"); scanf_s("%d", &balance); switch(option) { case 1: printf("Enter the amount you want to deposit\n"); scanf_s("%d", &decash); printf("Thank You\n"); printf("%d have been deposited in your account\n", decash); break; case 2: printf("Enter the amount you want to withdraw\n"); scanf_s("%d", &wicash); wibal=balance-wicash; printf("Thank You\n"); printf("%d have been withdrawed from your account\n", wicash); printf("Your balance is %d\n", wibal); break; case 3: printf("Your balance is Rs.%d\n", balance); break; default: printf("Invalid Input\n"); break; } getchar(); }
关于未识别的变量，请尝试将所有变量声明放在主块的顶部，例如：
int main() { int deposit, withdraw, kbalance, decash, wicash, wibal; char option; printf("Welcome to skybank\n");
C的旧变体在将变量声明与代码混合时皱眉。 据我所知，微软C实现的C标准是在C99之前，所以也许这可能就是问题所在。
您应该研究的其他几个问题：
scanf_s("%c",option); – option应该是&option因为您正在获取指向该变量的指针。
还在这里： case 1:
你想要'1' （如case '1' ）而不是普通1因为它是一个char ，而不是你想要的int 。
其他case检查也是case 。
关于scanf_s问题，尝试编译警告，编译器应该指出它。
最后，您可能想要删除您未使用的变量的代码，例如kbalance ， withdraw和deposit 。
在视觉c的变量声明中，在块的开头处进行。
例如
int main() { int deposit,withdraw,kbalance; char option; int decash,wicash int balance; int wibal; ...
试试这段代码：
#include #include int main() { printf("Welcome to skybank\n"); int deposit,withdraw,kbalance; char option; printf("Press 1 to deposit cash\n"); printf("Press 2 to Withdraw Cash\n"); printf("Press 3 to Know Your Balance\n"); scanf("%c",&option); int decash,wicash; switch(option) { int balance; printf("Enter your current Balance\n"); scanf("%d",&balance); case 1: printf("Enter the amount you want to deposit\n"); scanf("%d",&decash); printf("Thank You\n"); printf("%d have been deposited in your account\n",decash); break; case 2: printf("Enter the amount you want to withdraw\n"); scanf("%d",&wicash); int wibal; wibal=balance-wicash; printf("Thank You\n"); printf("%d have been withdrawed from your account\n",wicash); printf("Your balance is %d\n",wibal); break; case 3: printf("Your balance is Rs.%d\n",balance); break; default: printf("Invalid Input\n"); break; } getchar(); }
移动这个：
int balance; printf("Enter your current Balance\n"); scanf_s("%d",&balance);
在switch语句之前。