Thread: char array convert integer sum

user entered string -> a1b2c3

1+2+3 = 6
I need to sum the numbers in the string. but I couldn't.. i need help :c

Code:

#include <stdio.h>
#include <ctype.h>

#define SIZE 100


int main(int argc, char * argv[]){
    
    char cat[SIZE];
 
    printf("Veri gir:");
    
    gets(cat);
    int i, t=0;
    
    for(i=0;i < SIZE;i++){
        
        if(cat[i] == '\0')
            break;
        
        
        
        if(isalpha(cat[i]) == 0 ){
            printf("%c", cat[i]);
            
            t+=atoi(cat[i]);


        }
   
         
    }
    
    printf("Integer addition ->%d", t);
       printf("\n");
       return 0;
    

}

Don't use gets(), FAQ > Why gets() is bad / Buffer Overflows - Cprogramming.com

Why don't you use "isdigit()" instead of "isalpha()"? Just a suggestion, both ways are right, albeit opposite.

"atoi()" takes a string, not a char. Also, "kedi" doesn't exist.

Code:

#include <stdio.h>
#include <ctype.h>




#define SIZE 100


int main(int argc, char * argv[]){
    
    char cat[SIZE];
 
    printf("Enter String:");
    
    scanf("%s", &cat);
    int i, t=0;
    
    for(i=0;i < SIZE;i++){
        
        if(cat[i] == '\0')
            break;
  
        if(isdigit(cat[i]) == 1 ){
            t+=cat[i];


        }
   
         
    }
    
    printf("Integer addition ->%d", t);
       printf("\n");
       return 0;
    
}

i did like this. how will the sum now?

Code:

 

    char cat[SIZE];
 
    printf("Enter String:");
  
    scanf("%s", &cat);
    int i, t=0, x=0;
    
    for(i=0;i < SIZE;i++){
        
        if(cat[i] == '\0')
            break;
  
        if(isdigit(cat[i]) == 1 ){
            
            x = atoi(&cat[i]);
            t+=x;
        }
   
         
    }
    
    printf("Integer sum ->%d\n", t);
       return 0;
    
}

i figured this out and it worked

Thanks.

Problem is, you used the "&cat[i]" statement on line #15 without thinking what it actually does... Yes, it returns a "char*", yes it acts like a string, but is it the string you want?

Let's look at your second example, "a132c3". First character, it doesn't nothing. Second character, it takes that and EVERYTHING AFTER IT and tries to read an integer, therefore it reads "132". Third character, similar situation, reads "32". Then "2", Then nothing. Finally, it reads a "3". 132 + 23 + 2 + 3 = 169