c - 移动字符串数组中的元素并用零填充

Question

我想将数组中的元素向右移动并用零填充移动后的元素(作为字符串)。但这比我想象的要难一些。

这个程序读取一个包含两行的文本文件。每行包含一个整数(定义了最大长度)。它将每一行保存在一个单独的数组中。

稍后我需要将这两个数组转换为整数数组并进行一些算术运算。

为此，我需要确保这两个数组具有相同的长度

例如我的输入是:

num_first : 1859654

num_second:5654

现在我需要它们是:

num_First : 1859654(它比第二个数字大所以不会改变)

第二个数:0005654(比第一个小，所以我们需要添加那些前导零)

我如何根据两个输入的差异将那些前导零添加到数组？

最后我想将它们保存在数组中(作为字符串或整数)。

#include <stdio.h>
#include <string.h>
#define SIZE_MAX 20

int main()
{

FILE *fPTR;

    char num_first[SIZE_MAX]; // string input
    char num_second[SIZE_MAX];

    if ((fPTR = fopen("input.txt", "r")) == NULL) // our file contains two line of integers. one at each
    {
        puts("File could not be opened.");
    }
    else
    {
        if (fgets(num_first, SIZE_MAX, fPTR) != NULL) // reads first line and saves to num_first
            puts(num_first); // prints first number
        if (fgets(num_second, SIZE_MAX, fPTR) != NULL) // reads second line and saves to num_second
            puts(num_second); // prints second number
        fclose(fPTR);
    }

    // getting strings lengths
    int fLEN = strlen(num_first) - 1;
    int sLEN = strlen(num_second);


    int e = 0; // difference between two string lengths

    // here we get the difference and it's the place which i want to shif the arrays

    if (fLEN>sLEN) // first string is bigger than second
    {
        e = fLEN-sLEN;
    }
    else if (sLEN>fLEN) // second string is bigger than first
    {
        e = sLEN-fLEN;
    }
    else // there is no difference between two strings
    {
        e = fLEN-sLEN;
    }

}

编辑:我还有另一个想法，但它没有按预期工作。

if (fLEN>sLEN) // first string is bigger than second
    {
        e = fLEN-sLEN;
        for(i=e;i>=0;i--)
        {
            num_second[i+1] = num_second[i];
        }
        for(i=fLEN-e;i>=0;i--)
        {
            num_second[i] = '0';
        }
    }

编辑 2:(慢慢开始工作)打印更多零。试图修复它

    #include <stdio.h>
#include <string.h>
#define SIZE_MAX 20

int main()
{

FILE *fPTR;

    char num_first[SIZE_MAX]; // string input
    char num_second[SIZE_MAX];
    char num_second2[SIZE_MAX] = {0};
    int i = 0;
    char numbers[SIZE_MAX];

    if ((fPTR = fopen("input.txt", "r")) == NULL) // our file contains two line of integers. one at each
    {
        puts("File could not be opened.");
    }
    else
    {
        if (fgets(num_first, SIZE_MAX, fPTR) != NULL) // reads first line and saves to num_first
            puts(num_first); // prints first number
        if (fgets(num_second, SIZE_MAX, fPTR) != NULL) // reads second line and saves to num_second
            puts(num_second); // prints second number
        fclose(fPTR);
    }

    // getting strings lengths
    int fLEN = strlen(num_first) - 1;
    int sLEN = strlen(num_second);


    int e = 0; // difference between two string lengths
    int h = 4;

    // here we get the difference and it's the place which i want to shif the arrays

    if (fLEN>sLEN) // first string is bigger than second
    {
        e = fLEN-sLEN;
        while (i>= h)//for(i=e;i>=0;i--)
        {
            num_second2[i+h] = num_second[i];
            i++;
            h--;
        }
        for(i=fLEN-e;i>=0;i--)
        {
        //  num_second[i] = '0';
        }
    }
    else if (sLEN>fLEN) // second string is bigger than first
    {
        e = sLEN-fLEN;
    }
    else // there is no difference between two strings
    {
        e = fLEN-sLEN;
    }
    printf("\n%d\n", e);
        for (i = 0; i < SIZE_MAX; i++) // using c to print
    {
        printf("%d", num_second2[i]);
    }
    puts(num_second);
}

Answer 1

#include <stdio.h>
#include <string.h>
#define SIZE_MAX 20

int main()
{

    FILE *fPTR;

    char num_first[SIZE_MAX]; // string input
    char num_second[SIZE_MAX];
    char num_zeros[SIZE_MAX];//array for leading zeros
    int i = 0;
    char numbers[SIZE_MAX];

    if ((fPTR = fopen("input.txt", "r")) == NULL) // our file contains two line of integers. one at each
    {
        puts("File could not be opened.");
    }
    else
    {
        if (fgets(num_first, SIZE_MAX, fPTR) != NULL) // reads first line and saves to num_first
            puts(num_first); // prints first number
        if (fgets(num_second, SIZE_MAX, fPTR) != NULL) // reads second line and saves to num_second
            puts(num_second); // prints second number
        fclose(fPTR);
    }
    for ( i = 0; i < SIZE_MAX; i++)
    {
        num_zeros[i] = '0';//fill array with '0's
    }
    // getting strings lengths
    int fLEN = strlen(num_first);
    if ( fLEN && num_first[fLEN - 1] == '\n')
    {
        num_first[fLEN - 1] = '\0';//remove trailing newline
        fLEN--;
    }
    int sLEN = strlen(num_second);
    if ( sLEN && num_second[sLEN - 1] == '\n')
    {
        num_second[sLEN - 1] = '\0';//remove trailing newline
        sLEN--;
    }
    int e = 0; // difference between two string lengths
    // here we get the difference and it's the place which i want to shif the arrays
    if (fLEN>sLEN) // first string is bigger than second
    {
        e = fLEN-sLEN;
        num_zeros[e] = '\0';//terminate array leaving e leading zeros
        strcat ( num_zeros, num_second);
        strcpy ( num_second, num_zeros);
    }
    else if (sLEN>fLEN) // second string is bigger than first
    {
        e = sLEN-fLEN;
        while ( fLEN >= 0)//start at end of array
        {
            num_first[fLEN + e] = num_first[fLEN];//copy each element e items from current location
            fLEN--;// decrement length
        }
        while ( e)// number of leading zeros
        {
            e--;
            num_first[e] = '0';// set first e elements to '0'
        }
    }
    else // there is no difference between two strings
    {
        //e = fLEN-sLEN;
    }
    puts(num_first);
    puts(num_second);
    return 0;
}