I want to create a program in C to check for @ and . if typed in by user -


checking email address if user typed in @ , . symbols. how can fix code?

void emailaddress(){      char emailadd[50];      int emailaddl, i;     printf("please enter email address\n");     scanf("%s", emailadd);     emailaddl=strlen(emailadd);     for(i=0; i<=emailaddl; i++){         if(emailadd[i]!='@'){             printf("the entered email address incorrect. please re-enter email address , must contain '@' specifier\n");             emailadd=(int*)calloc(emailadd, sizeof(char));             scanf("%s", emailadd);         }         if(emailadd[i]!='.'){             printf("the entered email address incorrect. please re-enter email address , must contain '.' specifier\n");             emailadd=(int*)calloc(emailadd, sizeof(char));             scanf("%s", emailadd);         }         else             continue;     } }

the major problem code facing not c logical structure of function. if emailadd contains character different @ and/or different . ask new email address. that's not want.

let's structure problem. here want do:

  1. get user input
  2. check if input contains @
  3. if not, ask new input
  4. check if input contains .
  5. if not, aks new input

you don't want once, long user input correct. more precise want . after @ (otherwise email address stack.overflow@so valid.

consider approach implements behaviour defined above:

#include <stdio.h> #include <stdlib.h> #include <string.h>  int main() {     char emailadd[50];     size_t emailaddl;   /* use size_t instead of int */      /* email address first time */     printf("please enter email address\n");     scanf("%s", emailadd);     emailaddl=strlen(emailadd);      /* loop while address has wrong format */     while(1){         /* create flags: 0 character missing, 1 character found */         int at_flag=0;         int dot_flag=0;         emailaddl=strlen(emailadd);          /* loop through char array. have loop 0 array lenght -1*/         for(int i=0; i<emailaddl; i++){    /* can declare variables in loops */              /* if @ has been found, set flag */             if(emailadd[i] == '@'){                 at_flag=1;             }             /* if . has been found , @ has been found earlier, set flag */             if(at_flag && emailadd[i] == '.'){                 dot_flag=1;             }             /* if both flags have been set, can stop searching */             if(at_flag && dot_flag){                 break;             }         }          /* if no @ has been found, ask */         if(!at_flag){             printf("the entered email address incorrect. please re-enter email address , must contain '@' specifier\n");             scanf("%s", emailadd);         /* if @ has been found, no ., ask */         } else if(!dot_flag){             printf("the entered email address incorrect. please re-enter email address , must contain '.' specifier, after '@' specifier\n");             scanf("%s", emailadd);         /* otherwise leave loop */         } else{             printf("everything fine!\n");             break;         }     } }

let's try scenarios:

$ please enter email address $ stack.overflow  $ entered email address incorrect. please re-enter email address , must contain '@' specifier $ stack.overflow@so $ entered email address incorrect. please re-enter email address , must contain '.' specifier, after '@' specifier $ stack.overflow@so.com $ fine!

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