关于中缀表达式向后缀表达式转换的编程问题 求解答

[BH_Little_Lion]

#include<stdio.h> 
#include<string.h>
void PostFix(char *f)
{ char stack[100],x;  int i,k,top;
  top = 0;  stack[0]="#";  i = 0;  k = strlen(f);
  do {
    x = f[i];   
	 switch(x) 
    { case ')':
       while ((top>0) && (stack[top]!="("))
         printf(stack[top--]);
       top--;  break;
    case '+': '-':'*': '/': '^': '%':
       while ((top>0) && (isp(stack[top])>=icp(x))
          printf(stack[top--]);
          stack[++top]=x;  break;
    default: printf(x) ;}
   i=i+1;
  }
   while (i<=k);
while (top>=0);
   printf(stack[top--]);}

int isp(char x) /* 栈内优先级 */

{ 
int a;
switch(x) {
  case '+':a = 1;  break;
   case '-': a = 1;  break;
  case '*':
  a = 2; break;
  case '/':
  a = 2; break;
  case '%': a = 2; break;
  case '^': a = 3; break;
  case '(': a = 0; break;
  case ')': a = 0; break;
  default: a = 0; break; }
return a;}

int icp( char x) /* 栈外优先级 */

{ int a;
  switch(x) {
  case '+': a = 1;  break;
   case '-': a = 1;  break;
  case '*':
  a = 2; break;
  case '/':
  a = 2; break;
  case '%': a = 2; break;
  case '^': a = 4; break;
  case '(': a = 5; break;
  case ')': a = 0; break;
  default: a = 0; break; }
  return a;}

int main()
{	char f[100];
	printf("Please enter a char:\n");
	gets(f);
	PostFix(f);
	return 0;
}

打完代码发现好多问题 自己已经debug到这里了
求编程大神解答 ~debug一点是一点。。。
谢谢！

编译器提示错误有5 21 C:\Users\hp\Desktop\中缀表达式向后缀表达式的转换.cpp [Error] invalid conversion from 'const char*' to 'char' [-fpermissive]

10 39 C:\Users\hp\Desktop\中缀表达式向后缀表达式的转换.cpp [Error] ISO C++ forbids comparison between pointer and integer [-fpermissive]

11 28 C:\Users\hp\Desktop\中缀表达式向后缀表达式的转换.cpp [Error] invalid conversion from 'char' to 'const char*' [-fpermissive]

378 15 c:\program files (x86)\dev-cpp\mingw64\x86_64-w64-mingw32\include\stdio.h [Error] initializing argument 1 of 'int printf(const char*, ...)' [-fpermissive]

13 18 C:\Users\hp\Desktop\中缀表达式向后缀表达式的转换.cpp [Error] expected ';' before ':' token

17 22 C:\Users\hp\Desktop\中缀表达式向后缀表达式的转换.cpp [Error] invalid conversion from 'char' to 'const char*' [-fpermissive]

1 0 C:\Users\hp\Desktop\中缀表达式向后缀表达式的转换.cpp In file included from C:\Users\hp\Desktop\中缀表达式向后缀表达式的转换.cpp

378 15 c:\program files (x86)\dev-cpp\mingw64\x86_64-w64-mingw32\include\stdio.h [Error] initializing argument 1 of 'int printf(const char*, ...)' [-fpermissive]

22 22 C:\Users\hp\Desktop\中缀表达式向后缀表达式的转换.cpp [Error] invalid conversion from 'char' to 'const char*' [-fpermissive]

1 0 C:\Users\hp\Desktop\中缀表达式向后缀表达式的转换.cpp In file included from C:\Users\hp\Desktop\中缀表达式向后缀表达式的转换.cpp

378 15 c:\program files (x86)\dev-cpp\mingw64\x86_64-w64-mingw32\include\stdio.h [Error] initializing argument 1 of 'int printf(const char*, ...)' [-fpermissive]

[BH_Little_Lion]

我会啦 printf出的错