Thread: Add a char in front of a few string

Are you aware that the format specifier for printf has the notion of a field and field width, as well as fill character? You can just specify that the integer is to be printed with a field width of 5, to be filled with leading 0s.

Originally Posted by jc2020

I think it's the way the terminals works. They align data to the left. So when I add zero to the front every single line gets one. I threw every thing Alex had at it. It workd for char becaisr yoi can make adjustment. Every thing else works so I'll be using it for other stuff, but for now its back to the drawing board.

No, it has nothing to do with terminals. You're just doing it wrong. For example:

Code:

#include <stdio.h>

int main(void)
{
    unsigned int numbers[] = {0, 1, 12, 123, 1234, 12345};
    for (size_t i = 0; i < sizeof(numbers) / sizeof(numbers[0]); ++i)
    {
        printf("%05u\n", numbers[i]);
    }
    return 0;
}

Notice that the input must be integers, i.e., you read the numbers as integers, not strings. If you prefer or must work with strings (e.g., because the data isn't necessarily numeric), then this approach doesn't work, but the alternative is so simple:

Code:

#include <stdio.h>
#include <string.h>

int main(void)
{
    char numbers[][6] = {"0", "1", "12", "123", "1234", "12345"};
    for (size_t i = 0; i < sizeof(numbers) / sizeof(numbers[0]); ++i)
    {
        size_t len = strlen(numbers[i]);
        // Zero pad if needed:
        if (len < 5)
        {
            for (size_t j = 0; j < (5 - len); ++j)
            {
                putchar('0');
            }
        }
        // Print the value itself:
        printf("%s\n", numbers[i]);
    }
    return 0;
}

Once you have this down pat, you can then do other things like add other formatting as needed. The problem seems to be that you dived into something complex instead of putting your focus on something simple first.

zeros.c

Code:

#include <stdio.h>
#include <string.h>

#define FILE_SIZE_MAX 10000
#define NUMBER_SIZE_MAX 10

#define FILE_IMPORT "acct.txt"
#define FILE_EXPORT "acctnew.txt"

char importData[FILE_SIZE_MAX]; 
char exportData[FILE_SIZE_MAX]; 
char tmpData[NUMBER_SIZE_MAX];
char tmp[NUMBER_SIZE_MAX];

void import() {    
    memset(importData,0,sizeof(importData));
    memset(tmpData,0,sizeof(tmpData));
    FILE* file = fopen(FILE_IMPORT, "r");    
    while (fgets(tmpData, sizeof(tmpData), file)) {
        strcat(importData, tmpData); 
    };
    fclose(file);
};

char *fixNumber() {
    memset(tmp,0,sizeof(tmp));
    int addZeros = 5 - strlen(tmpData);    
    for (int i = 0; i < addZeros; i++) {
        strcat(tmp,"0");
    };
    strcat(tmp,tmpData);    
    memset(tmpData,0,sizeof(tmpData));
    return tmp;
};

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

    tmpData[0] = '\0'; 
    import(); int i; int count = 0;
    
    remove(FILE_EXPORT);
    FILE *exportFile = fopen(FILE_EXPORT, "a");

    for (i = 0; i < strlen(importData); i++ ) {        
        if (importData[i] == '\n') {                        
            if (count <= 4 && count != 0) {                                                   
                fprintf(exportFile, "%s\n", fixNumber());
            } else {                
                fprintf(exportFile, "%s\n", tmpData);
            };
            count = 0;
        } else {
            tmpData[count] = importData[i];
            count++;
        };
    };

    fclose(exportFile);

};

It is flawed and i threw it together really quick but i'm assuming it will help you on the way to a final product.

I'd be tempted to read the number into an integer (fscanf/%d), and then use fprintf with a format specifier (%05s)

Stucture's "solution" is total garbage.