syntax and parse error

i keep getting a syntax error on line 9 and parse errors on lines 31, 32, 33, and 38...and i dont know why. Can anyone help me?

#include stdio.h<> <-----there are all correct in the code but don't show on here
#include stdlib.h<>
#include math.h<> 

int hamlength;
int pbit;
int hamcode;

String char  *hamming = NULL;

void enter_params(){
    printf("Enter length of the Hamming code:_\n");
      scanf("%d",&hamlength);
 printf("Enter the parity(0=even, 1=odd):_\n");
      scanf("%d",&pbit);
    hamming = (char *)malloc(hamlength * sizeof(char));
}

void free_memory(){
if (开发者_JAVA技巧hamming != NULL)
    free (hamming);
return;
}

 1. List item

void correct_hamming(){
int errorBit=0;
int currentBit;
int i;
int j;
int k;
printf("Enter the Hamming Code:_\n");
scanf("%s", hamming);
for(i = 1, i < hamlength; i = i * 2){
for(j = i; j < hamlength; j += 2 * i){
for(k = j; k < hamlength && k < currentBit; k++){
        currentBit = currentBit ^ hamming [hamlength - k];
        if (k != i)
        currentBit = currentBit ^ hamming[hamlength - k];       
}
errorBit += ((currenttBit ^(hamming[hamlength - i] - '0')) + i);
}
}
}
int main(){
      int choice=0;
      while(choice!=3){
         printf("1) Set parameters\n");
         printf("2) Check Hamming Code\n");
         printf("3) Exit\n");        
         printf("Enter selection:_\n");
            scanf("%d",&choice);
         switch(choice){
            case 1: enter_params(); 
               break; 
            case 2:  correct_hamming();
               break;
           case 3: printf("dueces!");
                    break;


         }
      }
      return 0;
   }

#include stdio.h<> <-----there are all correct in the code but don't show on here
#include stdlib.h<>
#include math.h<> 

You meant

#include <stdio.h> 
#include <stdlib.h>
#include <math.h> 

?

String char *hamming = NULL;

What is String doing here? It is not a C keyword. Remove String from that line. Your code is full of syntax and logic errors.

 1. List item // should be commented

errorBit += ((currenttBit ^(hamming[hamlength - i] - '0')) + i);

Typo here currenttBit should be currentBit

for(i = 1, i < hamlength; i = i * 2)

Replace , with ;

In main() function

  int choice=0;
  while(choice!=3)

When would the user enter his choice?

String char * doesn't look right to me. You probably didn't mean to include String there.

Remove the "String" on line 9.

And change this line:

for(i = 1, i < hamlength; i = i * 2){

To this

for(i = 1; i < hamlength; i = i * 2){

I'm assuming that in your code "1. List item" isn't really there.

#include<stdio.h>    // this is the right way to include header files
#include<stdlib.h>
#include<math.h> 

String is not valid keyword/datatype of C in String char *hamming = NULL;

1. List item is not valid in C.