Check if input string exists in array of strings in C

Question

I'm new to C and I'm trying to solve a problem.

I want to ask for user to insert 5 colors in an array but want to check if string exists on the existing array (allowed colors), or not before it is added. I've tried with strcmp and some other ways but can figure out how to do it. Any help would be appreciated.

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

char *colors[] = {
    "green",
    "red",
    "blue",
    "yellow",
    "brown",
    "white",
    "black"
};
int n = 5, i, num, size = 7;
char input[5][7];

int main() {
    char *str = (char *)malloc(sizeof(char) * size);

    printf("Add 5 colors:\n ");

    for (i = 0; i < n; i++) {
        scanf("%s", input[i]);
        strcpy(str, input[i]);

        if (strcmp(colors[i], str) == 0) {
            printf("Exists!\n");
        }
    }

    for (int i = 0; i < n; ++i) {
        printf("%d %s\n", 1 + i, input[i]);
    }
    return 0;
}

Your code doesn't compile. Please provide a minimal, reproducible example, see stackoverflow.com/help/minimal-reproducible-example. — August Karlstrom
– August Karlstrom, Commented Dec 4, 2021 at 10:58
There is still a syntax error in your code. You also need to include the required header files. — August Karlstrom
– August Karlstrom, Commented Dec 4, 2021 at 11:46
I have compiled with 2 diferent compilers and Iḿ getting no error. Can you please tell me what is? — Bruno
– Bruno, Commented Dec 4, 2021 at 12:03
Does this answer your question? How to check if a string is in an array of strings in C? — Robert Harvey
– Robert Harvey, Commented Dec 4, 2021 at 17:33

chqrlie · Accepted Answer · 2021-12-05 00:12:16Z

0

You should add a nested loop to compare the input with every string in the reference array:

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

const char *colors[7] = {
    "green",
    "red",
    "blue",
    "yellow",
    "brown",
    "white",
    "black",
};

int main() {
    int n, i, j, num, size = 7;
    char input[5][8];

    printf("Add 5 colors:\n ");

    n = 0;
    while (n < 5) {
        if (scanf("%7s", input[n]) != 1)
            break;

        for (int j = 0; j < 7; i++) {
            if (strcmp(input[n], colors[j]) == 0) {
                printf("Exists!\n");
                n++;
                break;
            }
        }
    }
    for (int i = 0; i < n; ++i) {
        printf("%d %s\n", 1 + i, input[i]);
    }
    return 0;
}

answered Dec 5, 2021 at 0:12

chqrlie

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