如何修改单数字2的幂检测C语言程序以支持批量数字检测？

Got it, let's adjust your code so you can check multiple numbers easily! Here are a few practical approaches depending on how you want to input the values:

Approach 1: Loop to accept input until you choose to stop #

This lets you manually enter numbers one by one, and exit when you input a specific termination value (like -1):

#include <stdio.h>
//function prototype for checking power of two
int checkPowerofTwo(int n);

int main() {
    int num;
    printf("Enter numbers to test (type -1 to quit):\n");
    
    // Infinite loop until user enters -1
    while (1) {
        printf("Enter a number: ");
        scanf("%d", &num);
        
        if (num == -1) {
            printf("Closing program...\n");
            break;
        }
        
        if (checkPowerofTwo(num) == 1)
            printf("%d is a power of 2\n", num);
        else
            printf("%d is not a power of 2\n", num);
    }
    return 0;
}

//function body
int checkPowerofTwo(int x) {
    if (x == 0)
        return 0;
    while( x != 1) {
        if(x % 2 != 0)
            return 0;
        x /= 2;
    }
    return 1;
}

Approach 2: Batch-check a predefined array of numbers #

If you have a fixed set of numbers to test, store them in an array and loop through it:

#include <stdio.h>
//function prototype for checking power of two
int checkPowerofTwo(int n);

int main() {
    // Define your list of numbers here
    int numbers[] = {2, 4, 7, 8, 16, 17, 0, 32, 64};
    int arraySize = sizeof(numbers) / sizeof(numbers[0]); // Calculate how many elements are in the array
    
    printf("Testing batch of numbers:\n");
    for (int i = 0; i < arraySize; i++) {
        int currentNum = numbers[i];
        if (checkPowerofTwo(currentNum) == 1)
            printf("%d is a power of 2\n", currentNum);
        else
            printf("%d is not a power of 2\n", currentNum);
    }
    return 0;
}

//function body
int checkPowerofTwo(int x) {
    if (x == 0)
        return 0;
    while( x != 1) {
        if(x % 2 != 0)
            return 0;
        x /= 2;
    }
    return 1;
}

Approach 3: Pass numbers via command line arguments #

Run the program with numbers directly (e.g., ./powerChecker 2 8 10 16) using command line inputs:

#include <stdio.h>
#include <stdlib.h> // Needed for atoi() to convert strings to integers
//function prototype for checking power of two
int checkPowerofTwo(int n);

int main(int argc, char *argv[]) {
    // Make sure the user provided at least one number
    if (argc < 2) {
        printf("Usage: %s <number1> <number2> ...\n", argv[0]);
        return 1;
    }
    
    printf("Testing command line inputs:\n");
    // Loop through each argument (skip argv[0], which is the program name)
    for (int i = 1; i < argc; i++) {
        int num = atoi(argv[i]);
        if (checkPowerofTwo(num) == 1)
            printf("%d is a power of 2\n", num);
        else
            printf("%d is not a power of 2\n", num);
    }
    return 0;
}

//function body
int checkPowerofTwo(int x) {
    if (x == 0)
        return 0;
    while( x != 1) {
        if(x % 2 != 0)
            return 0;
        x /= 2;
    }
    return 1;
}

Quick Optimization Tip #

Your checkPowerofTwo function can be simplified (and made faster) using bitwise operations. A number is a power of 2 if it's non-zero and x & (x-1) equals 0 (this works because powers of 2 have exactly one '1' bit in binary):

int checkPowerofTwo(int x) {
    return (x != 0) && ((x & (x - 1)) == 0);
}

内容的提问来源于stack exchange，提问作者Someone