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[英]If i enter a value above 16383 in this C program that converts decimal to binary, it doesn't work. Why?
[英]Why isn't my program that converts decimal to binary printing correctly?
我有一個任務要求我將十進制數轉換為存儲在 char 數組中的 16 位 2 的補碼二進制表示。 我獲得了包含完整 main 方法和addOne
方法的啟動代碼。 我只需要完成flipBits
和magnitudeToBinary
方法。
我已經完成了這些方法,它們應該可以工作,但是我得到了字符串 output。 一個例子是:
Enter integers and convert it to 2's complement binary.
Non-numeric input terminates program.
27
Integer: 27, 2's complement binary:
這是代碼:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
void magnitudeToBinary(int n, char arr[], int numOfBits);
void flipBits(char arr[], int numOfBits);
void addOne(char arr[], int numOfBits);
int main(void) {
setvbuf(stdout, NULL, _IONBF, 0);
//Declare a char array with size 16 to simulate 16-bit binary
int numOfBits = 16;
char arr[numOfBits + 1];
arr[numOfBits] = '\0'; //set the terminating character
//Declare integer n to hold the decimal integer
int n = 0;
puts("Enter integers and convert it to 2's complement binary.");
puts("Non-numeric input terminates program.");
//Continually taking input and convert it to binary
while (scanf("%d", &n) == 1) {//if successfully read in ONE decimal integer
//Initialize the char array to all 0s (leave the terminating character unchanged)
for(int i = 0; i < numOfBits; i ++){
arr[i] = '0';
}
//Convert magnitude (absolute value) to binary
magnitudeToBinary(abs(n), arr, numOfBits);
//if the number is negative: flip all bits, then add 1.
if(n < 0){
//Flip all bits in char arr
flipBits(arr, numOfBits);
//Add 1
addOne(arr, numOfBits);
}
//Output binary:
printf("Integer: %d, 2's complement binary: %s\n", n, arr);
}
return EXIT_SUCCESS;
}
/* addOne: arithmatically add 1 to the binary simulated by character array
* INPUT: char arr[]: the character array holding the binary
* int numOfBits: the number of bits in the binary
* */
void addOne(char arr[], int numOfBits){
/* True table
* ******************************
* carry arr[i] | arr[i] carry
* 1 0 | 1 0
* 1 1 | 0 1
* 0 0 | 0 0
* 0 1 | 1 0
* *********************************/
char carry = '1';
for(int i = numOfBits - 1; i >= 0; i --){
if(carry != arr[i]){
arr[i] = '1';
carry = '0';
}
else if(carry == '1'){
arr[i] = '0';
}
else{
arr[i] = '0';
}
}
return;
}
/* flipBits: perform 1's complement on the binary, i.e., change 1 to 0, 0 to 1
* INPUT: char arr[]: the character array holding the binary
* int numOfBits: the number of bits in the binary *
* */
void flipBits(char arr[], int numOfBits){
//Implement your solution here
for(int i = 0; i < numOfBits; i++) {
if(arr[i] == '1') {
arr[i] = '0';
} else if(arr[i] == '0') {
arr[i] = '1';
}
}
return;
}
/* magnitudeToBinary: Convert a non-negative decimal integer to binary (stored in a char array)
* using division-remainder algorithm
* INPUT: int n: The decimal integer number to be converted
* char arr[]: the character array holding the binary
* int numOfBits: the number of bits in the binary *
* */
void magnitudeToBinary(int n, char arr[], int numOfBits){
//Implement the division-remainder algorithm here
int i = 0;
while (n > 0) {
arr[i] = n % 2;
n = n / 2;
i++;
}
return;
}
我只想看看正確的二進制 output。 現在我不確定這是否是我的錯誤,我的教授的錯誤,或者 Eclipse 是否在起作用。 任何幫助表示贊賞,謝謝!
嘗試從以下位置更改magnitudeToBinary() 中的行:
arr[i] = n % 2;
至
arr[i] = n % 2 == 1 ? '1' : '0';
您想將 '1' 或 '0' 的 ASCII 值寫入數組 - 而不是 n % 2 的結果。
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