代碼塊問題

Question

嗨，我正在做一段課程，並且我在收到錯誤消息時遇到困難，它們是：

error 'strtoul' was not declared in this scope
error 'print' was not declared in this scope
error 'printf' was not declared in this scope

我輸入的代碼是：

using namespace std;

int main (int argc, const char * argv[]) {

unsigned long int a, tmp;

a = strtoul("01011111000110001001001011010011",ULL,2);
print(a);

//We always work on "a" pattern
print(tmp = a >> 4);
print(tmp = a << 6);
print(tmp = a & (long int) 0x3);
print(tmp = a & (char) 0x3);
print(tmp = a | (unsigned short) 0xf00f);
print(tmp = a ^ (long int) 0xf0f0f0f0);

return 0;
}


//Function prints unsigned long integer in hexadecimal and binary notation
void print(unsigned long b)


{

    int i, no_bits = 8 * sizeof(unsigned long);
    char binary[no_bits];

    //Print hexadecimal notation
    printf("Hex: %X\n", b);

    //Set up all 32 bits with 0
    for (i = 0; i < no_bits; i++) binary[i] = 0;

    //Count and save binary value
    for (i = 0; b != 0; i++) {
        binary[i] = b % 2;
        b = b/2;
    }

    //Print binary notation
    printf("Bin: ");
    for (i = 0 ; i < no_bits; i++) {
        if ((i % 4 == 0) && (i > 0)) printf(" ");
        printf("%d", binary[(no_bits - 1) - i]);
    }
    printf("\n\n");
}

但是我不斷收到錯誤消息：

error 'strtoul' was not declared in this scope
error 'print' was not declared in this scope
error 'printf' was not declared in this scope

無論我嘗試什么，當我嘗試聲明它們時，我總是收到相同的錯誤消息，那里有任何幫助嗎？

非常感激，

本

Answer 1

您需要在程序頂部包括這些頭文件：

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

stdio庫允許您執行輸入/輸出操作， stdlib庫定義了幾個通用函數，包括將字符串轉換為無符號長整數。

您可能希望將print方法移至main之前，並且在調用strtoul時也應將ULL更改為NULL ，因為我認為這是一個錯字。 您可以在我提供的鏈接中查看文檔。