CODEWITHSUNDEEP
carrays
Nakib
Nakib

Reputation: 4703

How to check if a string is in an array of strings in C?

How to write below code in C? Also: is there any built in function for checking length of an array?

Python Code

x = ['ab', 'bc' , 'cd']
s = 'ab'

if s in x:
  //Code

Upvotes: 19

Views: 76680

Answers (4)

Matheus Santana
Matheus Santana

Reputation: 581

A possible C implementation for Python's in method could be

#include <string.h>

int in(char **arr, int len, char *target) {
  int i;
  for(i = 0; i < len; i++) {
    if(strncmp(arr[i], target, strlen(target)) == 0) {
      return 1;
    }
  }
  return 0;
}

int main() {
  char *x[3] = { "ab", "bc", "cd" };
  char *s = "ab";

  if(in(x, 3, s)) {
    // code
  }

  return 0;
}

Note that the use of strncmp instead of strcmp allows for easier comparison of string with different sizes. More about the both of them in their manpage.

Upvotes: 3

nvlass
nvlass

Reputation: 685

Something like this??

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

int main() {
    char *x[] = {"ab", "bc", "cd", 0};
    char *s = "ab";
    int i = 0;
    while(x[i]) {
        if(strcmp(x[i], s) == 0) {
            printf("Gotcha!\n");
            break;
        }
        i++;
    }
}

Upvotes: 12

Dimitar Slavchev
Dimitar Slavchev

Reputation: 1667

There is a function for finding string length. It is strlen from string.h

And then you could use the strcmp from the same header to compare strings, just as the other answers say.

Upvotes: 1

user93353
user93353

Reputation: 14039

There is no function for checking length of array in C. However, if the array is declared in the same scope as where you want to check, you can do the following

int len = sizeof(x)/sizeof(x[0]);

You have to iterate through x and do strcmp on each element of array x, to check if s is the same as one of the elements of x.

char * x [] = { "ab", "bc", "cd" };
char * s = "ab";
int len = sizeof(x)/sizeof(x[0]);
int i;

for(i = 0; i < len; ++i)
{
    if(!strcmp(x[i], s))
    {
        // Do your stuff
    }
}

Upvotes: 19

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