c - How to make a function that iterates an isalpha function work? -

i have program compares each element in string using isalpha. input string , calls function cycle through array , check if characters letters. if yes, prints true , false otherwise. problem can't seem make work right. return false every time.

#include <stdio.h> #include <string.h>  int isalpha(char string[]);  int main() {     char str[100];     int bool;      printf("enter string check: \n");     fgets(str, 100, stdin);      bool = isalpha(str);     if(bool != 0)     {         printf("true\n");     }     else if(bool == 0)     {         printf("false\n");     }     return 0;    }  int isalpha(char string[]) {     int i, check, len = strlen(string);     for(i = 0; < len; i++)     {         if(isalpha(string[i]))         {             check = 1;         }         else         {             check = 0;             break;         }     }     return check; } 

if user enters abc, returned string fgets abc\n\0. in other words, it's newline character fails isalpha test. can fix problem subtracting 1 string length. should initialize check variable since it's possible body of loop never run, e.g. if user presses enter without typing anything.

int i, check = 0; int len = strlen(string) - 1; for(i = 0; < len; i++) 

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as @shadowranger points out in comments, nothing simple in c. absolutely safe, should remove newline string shown below

int i, check = 0; string[strcspn(string, "\n")] = '\0'; int len = strlen(string); for(i = 0; < len; i++)