get the index of a char in a char array in C

Question

I got a error. "Passing argument 1 'strchr' makes pointer from integer without a cast"

How can I fix that ?

this happen in const char *ptr = strchr(c, ';'); and I'm trying to do is just get the index of a specific char in a char array.

In my File, I have for example 100 lines, and in each line, i has something like that 12345;Lucas , so I need to split this, numbers and letters and I'm trying to search the " ; " and separate.

Follow my code

FILE *fp;
char c;
char c2[100];
int i = 0;

fp = fopen("MyFile.csv", "r");

if (!fp) {
    printf("Error!\n");
    exit(0);
}

while((c = getc(fp)) != EOF){
    for (i = 0; i < 1; i++)
{

        const char *ptr = strchr(c, ';');
        if(ptr) {
           int index = ptr - c;
           printf("%d", index);
        }

    }
    printf("%c", c);
}

Answer 1

您的变量c是单个字符，而不是char数组。

Answer 2

There is no need to implement this on the basis of getc and strchr .

if your data is organized in lines, then you should use fgets to read the file line-wise. if your data is separated by ';' , then you should use sscanf to split the line buffer into substrings.

See this post for an example program that solves a similar problem.

Answer 3

strchr is used to search for a specific character within a NULL terminated string. To compare two characters simply use ==

if( c == ';' ) {
  // do something
}

Answer 4

this is crazy code! No idea what the for loop is.... maybe you want something like...

while(fgets(c2, 100, fp) != NULL)
{
    char* first = c2;
    char *second = c2;
            // look for a ;  or the end of the string...
    while(*second != ';' && *second != 0) second++;
    if(*second == 0) continue;  // if there was no ; just carry on to the next line
    *second = 0; second++; // put a terminator where the ; was

            // first will now point to the first string :- 123456
            // second will now point to the second part :-  Lucas
    printf("%s  %s\r\n", first, second);        
            // you may want to trim the second part of \r\n chars.
}

Answer 5

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

int main() {
    FILE *fp;
    char c;
    char c2[100];
    int i = 0;

    fp = fopen("MyFile.csv", "r");

    if (!fp) {
        printf("Error!\n");
        exit(-1);
    }

    while(NULL!=fgets(c2,100,fp)){//fgets read one line or 100 - 1 char 
        char *ptr = strchr(c2, ';');
        if(ptr) {
            int index = ptr - c2;
            printf("index of %c is %d\n", *ptr, index);
            *ptr = '\0';
            //12345;Lucas -> first is "12345", second is "Lucas"
            printf("split string first is \"%s\", second is \"%s\"\n", c2, ptr + 1);
        }
    }
    fclose(fp);

    return 0;
}