检查输入字符串是否存在于 C 的字符串数组中

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;
}

Answer 1

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;
}